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Kaposiform lymphangiomatosis is an uncommon generalized lymphatic anomaly with distinctive clinical, radiologic, histopathologic, and molecular findings. Herein, we document the pathology in 43 patients evaluated by the Boston Children's Hospital Vascular Anomalies Center from 1999 to 2020. The most frequent presentations were respiratory difficulty, hemostatic abnormalities, and a soft tissue mass. Imaging commonly revealed involvement of some combination of mediastinal, pulmonary, pleural, and pericardial compartments and most often included spleen and skeleton. Histopathology was characterized by dilated, redundant, and abnormally configured lymphatic channels typically accompanied by dispersed clusters of variably canalized, and often hemosiderotic, spindled lymphatic endothelial cells that were immunopositive for D2-40, PROX1, and CD31. An activating lesional NRAS variant was documented in 9 of 10 patients. The clinical course was typically aggressive, marked by hemorrhage, thrombocytopenia, diminished fibrinogen levels, and a mortality rate of 21%., Competing Interests: Conflicts of Interest and Source of Funding: The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Importance: Vascular anomalies of the head and neck are relatively rare lesions. Management is challenging because of the high likelihood of involvement of functionally critical structures. Multiple modalities of treatment exist for vascular anomalies of the head and neck, including medical therapies, sclerotherapy and embolization procedures, and surgery. This review focuses on the accurate diagnosis and the relative roles of the various therapeutic options., Observations: Vascular anomalies are classified by the International Society for the Study of Vascular Anomalies into 2 major groups: vascular tumors and vascular malformations. Vascular tumors encompass proliferative lesions ranging from infantile and congenital hemangiomas to kaposiform hemangioendothelioma. Alternatively, vascular malformations are embryologic errors in vasculogenesis. This article focuses on the management of vascular malformations. The 3 primary vascular malformation subclassifications are lymphatic, venous, and arteriovenous. The burden of disease, diagnosis, and current management options are discussed in detail for each subtype., Conclusions and Relevance: Most vascular malformations of the head and neck require a multidisciplinary approach. Available medical, interventional radiologic, and surgical interventions are constantly evolving. Optimization of function and cosmesis must be balanced with minimization of treatment-associated morbidity. Otolaryngologists-head and neck surgeons must remain up to date regarding options for diagnosis and management of these lesions.

Vascular tumors in pediatric patients are an important entity for the clinician to recognize and correctly diagnose. They may present at birth or develop at any point during infancy, childhood, or adolescence. Most are benign, but even benign lesions may have significant morbidity without proper intervention. Malignant vascular tumors are also rarely seen in the pediatric population, and may be associated with various syndromes., (Copyright © 2020 Hinen, Trenor and Wine Lee.)

Background: The incidence of venous thromboembolism (VTE) after elective surgery in children with mobility impairments, including those with a neuromuscular complex chronic condition (NCCC), is unknown. Therefore, our objectives were to assess the incidence of VTE after elective spine and lower-extremity surgery in children with NCCC., Methods: A retrospective analysis of children with NCCC undergoing elective lower-extremity and/or spinal surgeries from 2005 to 2009 included in the Pediatric Health Information Systems Plus (PHIS+) database. VTE during hospitalization for surgery was assessed through abstraction and review of ultrasound (U/S) and computed tomography results by 2 independent reviewers. VTEs related to pre-existing central venous catheters were excluded., Results: There were 4,583 children with NCCC who underwent orthopaedic surgery during the study period at 6 centers. Most were male (56.3%), non-Hispanic whites (72.7%), and had private insurance (52.2%). The most common NCCC diagnoses were cerebral palsy (46.7%), brain and spinal cord malformations (31.1%), and central nervous system degenerative conditions (14.5%). Forty children (0.9%) underwent U/S to assess VTE. Eighteen children (0.4%) underwent computed tomography to assess VTE. Four children (with cerebral palsy) had a positive U/S for a lower-extremity VTE (10-18 y of age), yet 2 had their VTE before surgery. Therefore, the adjusted VTE rate for children with NCCC undergoing orthopaedic lower-extremity or spine surgery was 4 per 10,000 (2 cases per 4583 surgeries). Each of the 2 cases had a known coagulation disorder preoperatively. Only 10% of the cohort used compression devices, 3% enoxaparin, and 1.6% aspirin for prophylaxis., Conclusion: The rate of non-central-venous-catheter-related VTE associated with orthopaedic surgery in children with NCCC is very low and lower than rates reported in healthy children., Significance: To our knowledge, this is the first multi-institutional study reporting the incidence of VTE in children with NCCCs undergoing elective hip and spine surgery. These data support no additional prophylaxis is required in children with NCCC undergoing elective hip and spine surgery unless other known risk factors are also present.

Background: Fibroadipose vascular anomaly (FAVA) is a recently-defined vascular malformation often involving the extremities and presenting in childhood. Patients may present to orthopaedic surgeons with pain, swelling, joint contractures, and leg length discrepancy. There is no established therapy or treatment paradigm. We report on outcomes following surgical excision for patients with this condition., Methods: Between 2007 and 2016, all 35 patients that underwent excision of lower-extremity FAVA were retrospectively reviewed using a combination of medical records, radiologic findings, and telemedicine reviews., Results: Mean age at initial presentation was 12.3±6.8 years. Mean follow-up from time of definitive diagnosis at our institution was 66 months (range: 12 to 161 mo). Mean follow-up after surgery was 35 months (range: 6 to 138 mo). Females were affected more than males (71% vs. 29%). The most common location of FAVA was in the calf (49%), followed by the thigh (40%). The most commonly involved muscle was gastrocnemius (29%), followed by the quadriceps (26%). At latest follow-up after surgery, there was an improvement in the proportion of patients with pain at rest (63% vs. 29%), pain with activity (100% vs. 60%), as well as analgesia use (94% vs. 37%). Fourteen patients (40%) had symptomatic residual disease or recurrence of FAVA requiring further treatment. Six patients (17%) required further surgery and 6 (17%) required further interventional radiologic procedures. Three patients (9%) required eventual amputation for intractable pain and loss of function. Lesions with direct nerve involvement were associated with persistent neuropathic symptoms at latest follow-up (P=0.002) as well as symptomatic residual disease and/or recurrence requiring further treatment (P=0.01). Seventeen patients (49%) had 19 preoperative joint contractures. Eighteen of the 19 contractures (95%) had sustained improvement at latest follow-up., Conclusions: In carefully selected patients, surgical excision of FAVA results in improvement of symptoms. However, symptomatic residual disease and/or recurrence are not uncommon. Direct nerve involvement is associated with a worse outcome., Level of Evidence: Level IV-case series.

Objective: Complicated lymphatic anomalies (CLAs) are chronic, progressive, and debilitating conditions that share clinical features, yet key elements for optimal evaluation and management have not been established. We aimed to formulate expert opinion consensus-based guidelines for comprehensive evaluation of CLAs., Study Design: Patient support groups dedicated to CLAs organized an international conference for vascular anomaly experts from 16 specialties to address the objective. Participants received a set of questions before the meeting and reviewed the literature. Data extracted from international lymphatic anomaly registries were presented and the group separated for panel discussions during the conference. The recommendations achieving consensus within the panel were presented to the entire audience. Open debate occurred until majority approval was achieved., Results: The expert group was composed of 52 physicians who defined the clinical elements required to evaluate and diagnose a CLA. The radiology panel established the preferred anatomical and functional imaging methods for diagnosis and the elements required to be described during interpretation. Two medical panels compiled the metabolic and hematologic tests at diagnosis and also recommended functional studies. The surgical group recommended precautions for biopsy and the pathology panel provided biopsy specimen processing guidelines., Conclusions: Patients with CLAs require a comprehensive and targeted diagnostic plan for appropriate management, prevention of complications, and conservation of resources. As this population is managed by diverse medical and surgical specialties, we offer an expert multidisciplinary consensus-based opinion on the current literature and on data extracted from international lymphatic anomaly registries., (© 2019 Wiley Periodicals, Inc.)

Purpose: Fibroadipose vascular anomaly (FAVA) is an intramuscular vascular malformation that has been recently described as a distinct clinical entity. The clinical, radiological, and histopathological characteristics of FAVA in the upper extremity are reviewed., Methods: This was a retrospective case series of upper-extremity FAVA lesions., Results: We reviewed 19 patients with FAVA of the upper limb. Pain, stiffness, swelling, and flexion contractures were the most common presentations. Except for one lesion confined to the hand, all lesions either presented with or developed a contracture within 10 years. Ten patients underwent surgical debulking. Six required tendon transfer reconstruction and 3 necessitated a free functional muscle transfer., Conclusions: Fibroadipose vascular anomaly in the upper extremity requires an accurate diagnosis and may benefit from early referral to a multidisciplinary vascular anomaly center with experienced hand surgeons. Compression garments, propranolol, and sclerotherapy seem to be ineffective. Surgical resection focused on symptomatic regions with appropriate reconstruction may have benefit in salvage of limbs with compromised function., Type of Study/level of Evidence: Therapeutic IV., (Copyright © 2020 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Objective: Juvenile nasopharyngeal angiofibroma (JNA) is a rare vascular tumor of unknown etiology. Studies investigating the molecular and genetic determinants of JNA are limited by small sample size and inconsistent approaches. The purpose of this study is to examine all eligible JNA studies in aggregate, applying qualitative analysis to highlight areas of particular relevance, including potential targets for therapeutic intervention., Methods: The PubMed, MEDLINE, Embase, Web of Science, Cochrane, and CINAHL databases were screened with inclusion and exclusion criteria applied to all citations. Manuscripts investigating the genetic determinants, histopathogenesis, and heritability of juvenile nasopharyngeal angiofibroma were included. Non-English studies, case reports, and articles focusing on clinical management without original data were excluded. Full text articles were obtained. A qualitative synthesis of data was performed., Results: A total of 59 articles met criteria for inclusion. These were divided into 6 categories based on the primary topic or target discussed, (1) steroid hormone receptors, (2) chromosomal abnormalities, (3) growth factors, (4) genetic targets, (5) molecular targets, (6) Wnt cell signaling, and (7) studies that overlapped multiple of the aforementioned categories. Although relatively low n values prevent definitive conclusions to be drawn, a predominance of certain molecular targets such as vascular endothelial growth factor (VEGF) and Wnt/β-catenin pathway intermediaries is apparent., Conclusions: Although the etiology of JNA remains elusive, contemporary molecular genetic investigation holds promise for risk stratification and could form the basis of a modernized staging system. A multicenter clinical registry and linked tissue bank would further promote the search for JNA specific biomarkers.

Purpose-Objective: Epithelioid hemangioendothelioma (EHE) is a rare vascular malignancy with varying biologic behavior. The purpose of this study was to identify imaging findings most characteristic of EHE., Methods: Retrospective review of clinical and imaging records in patients referred to our Vascular Anomalies Center over a 17 year period with biopsy proven EHE., Results: We evaluated 29 patients (17 F) with median age of 16 years (range 2-76 y). The most common presenting symptoms were pain (n = 13) and palpable mass (n = 7). 22 (70%) had multifocal disease. Most common sites of involvement were lung (n = 25), liver (n = 16), bone (n = 12), soft tissue (n = 3) and lymph nodes (n = 1). Of patients with single site disease, 3 had lung, 3 liver, and 1 had bone lesions. In 18/25 with lung disease, there were multiple nodules of varying sizes and characteristics. In 14/16 with hepatic disease there were multiple nodules with predominantly peripheral distribution. Subcapsular retraction was seen in 10/16 and a "lollipop" sign (hepatic or portal vein tapering at the edge of a well-defined hypoenhancing lesion) identified in 5/16. Of 12 osseous lesions, 11 were lytic, 8 involved vertebrae and 9 involved the axial skeleton., Conclusion: EHE has varied imaging findings. The most common sites are lungs, liver, and bone, with multi-organ involvement seen in most. Lung disease is most commonly characterized by multiple nodules. Hepatic lesions demonstrate the most distinctive findings, with peripheral distribution, lack of early enhancement, subcapsular retraction and "lollipop" sign. Osseous lesions are commonly lytic and more prevalent in the axial skeleton., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Central conducting lymphatic anomalies (CCLA) may cause chylous leaks and protein-losing enteropathy (PLE) owing to dysfunction of the central lymphatic channels. Most of the treatment strategies for these conditions are palliative and provide transient improvement., Methods: We treated 14 patients with intractable chylous leak and/or PLE using a novel technique of lymphaticovenous bypass of the terminal portion of the thoracic duct. Chylous leaks occurred in multiple different anatomic sites. All patients had CCLA and failure of thoracic duct emptying demonstrated by preoperative intranodal lymphangiography., Results: Five patients had complete resolution of symptoms, and two patients had partial improvement. There were no major complications. Of 5 patients with PLE, only one improved after lymphaticovenous bypass. Repeat traditional lymphangiography was performed in 4 patients who did not improve, demonstrating patency of the bypass in all cases with persistent sluggish drainage. One patient had repeat MR lymphangiography that did not show the thoracic duct well., Conclusions: Bypass of the terminal thoracic duct is a novel procedure that offers improvement and a chance of cure for some patients with devastating manifestations of CCLA who lack other effective therapeutic options., Level of Evidence: IV., (Copyright © 2018. Published by Elsevier Inc.)

Objective: To define the types of hepatic hemangiomas using the updated International Society for the Study of Vascular Anomalies classification and to create a set of guidelines for their diagnostic evaluation and monitoring., Study Design: We used a rigorous, transparent consensus protocol defined by an approved methodology, with input from multiple pediatric experts in vascular anomalies from hematology-oncology, surgery, pathology, radiology, and gastroenterology., Results: In the first section, we define the subtypes of hepatic hemangiomas based on the clinical course, histology, and radiologic characteristics. We recommend against using the term "hemangioma" for any vascular malformations affecting the liver or any hypervascular tumors that are not characterized by the approved definitions. We recommend against using the term "hemangioendothelioma" for infantile or congenital hemangioma. The following 2 sections dedicated to infantile hepatic hemangioma and to congenital hepatic hemangioma individually describe these subtypes in further detail, including complications to be considered during monitoring and respectively recommended screening evaluations., Conclusions: Although institutional variations may exist for specific clinical details, a clear understanding of the diagnosis of hepatic hemangiomas affecting children and the possible complications that require screening during the monitoring period should be standard. As children with hepatic hemangiomas are managed by different medical and surgical specialties, we offer an expert opinion multidisciplinary consensus based on current literature and on data extracted from the liver hemangioma registry., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Patients undergoing surgery for congenital heart disease are at high risk for bleeding as well as thrombosis in the postoperative period. The objective of the study was to describe the design and effects of implementing a standardized unfractionated heparin anticoagulation protocol for children after congenital heart surgery., Methods: We created a tiered guideline for the postoperative management of bleeding and thrombosis. In patients treated with unfractionated heparin, anti-factor Xa activity level as well as activated partial thromboplastin time were used for dose titration. Clinical outcomes, including bleeding and thrombosis events, were prospectively collected for 5 months before and after protocol implementation and adjudicated as either minor, clinically relevant nonmajor, or major., Results: Among 792 surgical patients followed during the study period, a total of 203 patients (87 preimplementation, 116 postimplementation) were treated with therapeutic unfractionated heparin over a total of 1481 patient days. Of these, 28% were neonates and 35% were infants (29 days to 1 year), with a trend toward fewer neonates and lower Risk Adjustment for Congenital Heart Surgery (RACHS) scores after protocol implementation. Among 1321 time-matched pairs, activated partial thromboplastin time and antifactor Xa activity levels were poorly correlated (r 2  = 0.33). Clinically relevant bleeding events, which required increased medical care, including blood transfusion, decreased after protocol implementation (4.14 vs 1.62 bleeding events per 100 patient-days; risk ratio, 0.39 [0.20-0.75]; P = .005), even after correcting for differences in age and RACHS scores (P = .006). This finding was primarily found after RACHS category 1 to 3 procedures (risk ratio, 0.27 [0.10-0.73]; P = .0099) and in noninfants (risk ratio, 0.25 [0.09-0.65]; P = .005). There were no significant differences in the incidences of major bleeding (P = .88) or any thrombosis (P = .55)., Conclusions: The use of a standardized anticoagulation protocol is feasible and might reduce the incidence of bleeding and thrombosis events in postcardiotomy patients., (Copyright © 2018 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Case: Gorham-Stout disease (GSD) is a rare entity that is marked by progressive osteolysis and bone resorption. A 14-year-old boy who was being followed for scoliosis presented with a marked curve progression and kyphoscoliosis. Imaging revealed osteolysis of the posterior elements and the ribs, suggestive of GSD. The structural compromise threatened spinal cord compression. Preoperative sirolimus therapy was initiated to stabilize the disease prior to corrective instrumentation. A biopsy specimen that was obtained at the time of instrumentation showed lymphatic vascular spaces consistent with GSD. Sirolimus therapy with the addition of bisphosphonate therapy was continued postoperatively., Conclusion: To our knowledge, this case report is the first to describe sirolimus therapy combined with surgery for GSD of the spine. The patient did well with consecutive medical optimization and surgical intervention, including postoperative sirolimus and bisphosphonate therapy.

Objectives: Anticoagulation with unfractionated heparin (UFH) after pediatric cardiac surgery can be monitored using either activated partial thromboplastin time (aPTT) or anti-factor Xa activity (anti-Xa). However, correlation of bleeding with either of these laboratory values has not been established. We sought to determine the correlation between bleeding events and aPTT and anti-Xa in patients who undergo anticoagulation after congenital heart surgery., Methods: We prospectively studied pediatric patients treated with UFH after cardiac surgery over an 11-month period. Bleeding events were prospectively assessed and adjudicated. The highest aPTT and corresponding anti-Xa for the 24 hours before bleeding events were collected to assess for association with bleeding. Statistical analysis was performed using generalized additive logistic regression., Results: A total of 202 patients received UFH over 1488 patient-days. The median age at surgery was 0.4 years (interquartile range, 0.1-2.2). A total of 45 major or clinically relevant bleeding events were observed. The correlation between aPTT and anti-Xa was of moderate strength (R = 0.58; P < .001). The odds of bleeding increased significantly when aPTT exceeded 150 (odds ratio, 1.71 per 10-second increase in aPTT, 95% confidence interval, 1.21-2.42; P = .003). Anti-Xa was not associated with bleeding (odds ratio, 1.11 per 0.1 IU/mL increase, 95% confidence interval, 0.89-1.29; P = .34)., Conclusions: In heparinized pediatric patients after cardiac surgery, increased risk of bleeding is more closely associated with elevated aPTT levels than elevated anti-Xa levels. In addition to anti-Xa, monitoring of aPTT levels should be considered during titration of UFH in pediatric patients after cardiac surgery., (Copyright © 2018 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Objective: Patients with Klippel-Trénaunay syndrome (KTS) and congenital lipomatous overgrowth, vascular malformations, epidermal nevi, and spinal/skeletal abnormalities (CLOVES) syndrome have central phlebectasia and enlarged persistent embryonic veins that are often incompetent and prone to thromboembolism. The purpose of the study was to determine the presence of phlebectasia and the incidence of symptomatic pulmonary embolism (PE)., Methods: A retrospective review was conducted of patients referred to the Vascular Anomalies Center at our institution during a 21-year period who were diagnosed with KTS and CLOVES syndrome. Of these, the patients who had PE were screened for thromboembolic risk factors in addition to phlebectasia and the presence of persistent embryonic veins. Treatment outcomes following subsequent endovascular and medical therapies were reported., Results: A total of 12 KTS patients of 96 (12.5%) and 10 CLOVES syndrome patients of 110 (9%) suffered PE. Fourteen patients (64%) developed PE after surgery or sclerotherapy. All of the patients had abnormally dilated central or persistent embryonic veins; 20 patients were treated with anticoagulation (1 died at the time of presentation, and no information was available for 1) after PE, and 14 (66%) patients underwent subsequent endovascular treatment. Five patients developed recurrent PE despite anticoagulation. Two of the patients died of PE. No patients treated with endovascular closure of dilated veins had subsequent evidence of PE., Conclusions: Patients with KTS and CLOVES syndrome are at high risk for PE, particularly in the postoperative period., (Copyright © 2018 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Objective: To assess the association of placental abnormalities with neonatal stroke., Study Design: This retrospective case-control study at 3 academic medical centers examined placental specimens for 46 children with neonatal arterial or venous ischemic stroke and 99 control children without stroke, using a standard protocol. Between-group comparisons used χ 2 and Fisher exact t test. Correlations used Spearman correlation coefficient., Results: Case placentas were more likely than controls to meet criteria for ≥1 of 5 major categories of pathologic abnormality (89% vs 62%; OR, 5.1; 95% CI, 1.9-14.0; P = .0007) and for ≥2 categories (38% vs 8%; OR, 7.3; 95% CI, 2.9-19.0; P < .0001). Fetal vascular malperfusion occurred in 50% of cases and 17% of controls (OR, 4.8; 95% CI, 2.2-10.5; P = .0001). Amniotic fluid inflammation occurred in 46% of cases with arterial ischemic stroke vs 25% of controls (OR, 2.6; 95% CI, 1.1-6.1; P = .037). There was evidence of a "stress response" (meconium plus elevated nucleated red blood cells) in 24% of cases compared with 1% of controls (OR, 31; 95% CI, 3.8-247.0; P < .0001)., Conclusions: Placental abnormality was more common in children with neonatal stroke compared with controls. All placental findings represent subacute-to-chronic intrauterine stressors. Placental thrombotic processes were associated with both arterial and venous stroke. Our findings provide evidence for specific mechanisms that may predispose to acute perinatal stroke. Amniotic fluid inflammation associated with neonatal arterial ischemic stroke deserves further investigation., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objective: Lymphatic malformations (LMs) are challenging to manage, particularly those involving the cervicofacial region and airway. Traditional therapy is sclerotherapy and/or resection. We aim to establish the emerging therapeutic role of sirolimus., Study Design: Institutional review board-approved retrospective review., Methods: All patients treated for cervicofacial LM with sirolimus at Boston Children's Hospital, Massachusetts, from November 2012 to October 2016 were included. Chart review included response to therapy (defined as reduction in LM bulk by clinical photographs and radiologic imaging), type of LM (microcystic, macrocystic, mixed), extent of disease, duration of therapy, patient/parent-reported quality-of-life, airway status (tracheostomy dependence), and complications (opportunistic infection, hemorrhage, other). Follow-up and clinical outcomes were included up until October 2016., Results: Nineteen patients were treated with sirolimus for cervicofacial LM from November 2012 to October 2016 at Boston Children's Hospital. Seven patients remain on uninterrupted sirolimus. Of 12 patients who stopped therapy, seven have resumed due to recurrence of symptoms. All patients demonstrated reduction in LM bulk, ranging from modest to significant. All patients with mucosal vesicles (n = 14) resolved or improved on sirolimus. Six patients developed cellulitis, and four had bleeding within the LM during treatment. No patients developed opportunistic or systemic bacterial infection., Conclusion: The use of sirolimus in the management of cervicofacial LM often is efficacious, with limited adverse events. Long-term follow-up, durability of response, and coordination of sirolimus prior to procedural therapies need further study., Level of Evidence: 4. Laryngoscope, 128:269-276, 2018., (© 2017 The American Laryngological, Rhinological and Otological Society, Inc.)

Background: CLOVES syndrome is associated with somatic mosaic PIK3CA mutations and characterized by congenital lipomatous overgrowth, vascular malformations, epidermal nevi, and skeletal anomalies. Wilms tumor (WT) is a malignant embryonal renal neoplasm associated with hemihypertrophy and certain overgrowth disorders. After identifying WT in a child with CLOVES, we questioned whether ultrasonographic screening was necessary in these patients., Methods: We retrospectively reviewed patients with CLOVES syndrome in our Vascular Anomalies Center at Boston Children's Hospital between 1998 and 2016 to identify those who developed WT. A PubMed literature search was also conducted to find other patients with both conditions., Results: A total of 122 patients with CLOVES syndrome were found in our database (mean age 7.7 years, range 0-53 years). Four patients developed WT; all were diagnosed by 2 years of age. The incidence of WT in our CLOVES patient population (3.3%) was significantly greater than the incidence of WT in the general population (1/10,000) (P < 0.001). Four additional patients with WT and CLOVES syndrome were identified in our literature review., Conclusion: Patients with CLOVES syndrome have an increased risk of WT. Given the benefits of early detection and treatment, children with CLOVES syndrome should be considered for quarterly abdominal ultrasonography until age 7 years. Screening may be most beneficial for patients under 3 years of age., (© 2017 Wiley Periodicals, Inc.)

Essentials Perioperative thrombosis is a major cause of morbidity and mortality in congenital heart disease. Neonates and infants undergoing repair of congenital heart lesions were prospectively followed. Elevated von Willebrand factor (VWF) to ADAMTS-13 activity ratios typified the postoperative period. Thrombosis was associated with preoperative VWF activity and cryoprecipitate transfusion SUMMARY: Background The surgical repair of congenital heart malformations is frequently complicated by perioperative thrombosis of unclear etiology. An imbalance between von Willebrand factor (VWF) and ADAMTS-13 is an emerging variable in thrombosis. Objectives To describe perioperative changes to VWF, ADAMTS-13 and NETosis, and evaluate clinical and biochemical associations with postoperative thrombosis. Methods Neonates and infants undergoing palliation or definitive surgical repair of congenital heart malformations were recruited (n = 133). Preoperative and postoperative plasma levels of VWF, ADAMTS-13 and markers of NETosis were determined. Patients were followed for up to 30 days for the occurrence of thrombosis. Univariate and multivariate logistic regression analyses were conducted to identify variables associated with thrombosis. Results We identified significant postoperative increases in VWF activity, VWF level, DNA-histone complexes and cell-free DNA with an overall decrease in ADAMTS-13 activity. Patients experiencing postoperative thrombotic events (9%) were characterized by surgery performed at a lower intraoperative temperature, higher preoperative lactic acid levels, and higher preoperative VWF activity and level. A multivariate logistic regression model identified preoperative VWF activity (odds ratio (OR) 8.39 per IU mL -1 , 95% confidence interval [CI] 1.73-40.55) and transfusion of cryoprecipitate (OR 1.10 per mL kg -1 , 95% CI 1.03-1.17) as being associated with thrombosis. Conclusions Pediatric patients undergoing surgical repair of congenital heart malformations are exposed to high levels of VWF with diminished or minimal change to ADAMTS-13 in the immediate postoperative period. Elevated preoperative VWF activity is associated with postoperative thrombosis in pediatric congenital heart disease., (© 2017 International Society on Thrombosis and Haemostasis.)

Children who present with acute transient focal neurologic symptoms raise concern for stroke or transient ischemic attack. We present a series of 16 children who presented with transient focal neurologic symptoms that raised concern for acute stroke but who had no evidence of infarction and had unilateral, potentially reversible imaging features on vascular and perfusion-sensitive brain MR imaging. Patients were examined with routine brain MR imaging, MRA, perfusion-sensitive sequences, and DWI. Fourteen (88%) children had lateralized MRA evidence of arterial tree pruning without occlusion, all had negative DWI findings, and all showed evidence of hemispheric hypoperfusion by susceptibility-weighted imaging or arterial spin-labeling perfusion imaging at presentation. These findings normalized following resolution of symptoms in all children who had follow-up imaging (6/16, 38%). The use of MR imaging with perfusion-sensitive sequences, DWI, and MRA can help to rapidly distinguish children with conditions mimicking stroke from those with acute stroke., (© 2017 by American Journal of Neuroradiology.)

Objectives: Thrombosis is associated with increased morbidity and mortality in pediatric patients undergoing cardiac surgery. Although aspirin commonly is used for thromboprophylaxis, the utility of laboratory-based tests that assess aspirin efficacy have not been evaluated. We sought to determine the relationship between platelet aggregation testing and aspirin dose adjustment on thrombosis rates in this population., Methods: Pediatric patients undergoing cardiac surgery who received aspirin and underwent platelet testing were studied retrospectively. Patients were excluded if they were treated with multiple agents or experienced thrombosis before the initiation of aspirin. Thrombosis events within 30 days after initiation of aspirin were recorded. Associations between aspirin responsiveness and thrombosis rate and aspirin dose adjustment and thrombosis rate were assessed with the use of multivariable logistic regression analysis., Results: Suboptimal platelet response to aspirin was detected in 64 of 430 patients (15%) and thrombosis was detected in 11 patients (2.6%). Lack of aspirin responsiveness on initial testing was a significant risk factor for thrombosis (P < .001) independent of age, weight, diagnosis, and initial aspirin dose. Dose escalation based on aspirin testing was performed in 40 of 64 patients, and significantly lower rate of thrombosis was observed in patients who underwent dose escalation compared with those without dose escalation (0/40 vs 9/24, P < .001). By multivariable analysis, the only significant independent risk factor for thrombosis was failure to increase aspirin dose after initial unresponsiveness (P < .001)., Conclusions: Current practice of weight-based aspirin dosing may lead to subtherapeutic platelet inhibition in some children. Aspirin unresponsiveness is associated with increased risk of thrombosis after specific pediatric cardiac surgical procedures. Aspirin dose increase in unresponsive patients is associated with reduced risk of thrombosis., (Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background and Purpose: Perinatal stroke, including neonatal and presumed perinatal presentation, represents the age in childhood in which stroke occurs most frequently. The roles of thrombophilia, arteriopathy, and cardiac anomalies in perinatal ischemic stroke are currently unclear. We took a uniform approach to perinatal ischemic stroke evaluation to study these risk factors and their association with recurrent stroke., Methods: We reviewed records of perinatal stroke patients evaluated from August 2008 to February 2016 at a single referral center. Demographics, echocardiography, arterial imaging, and thrombophilia testing were collected. Statistical analysis was performed using Fisher exact test., Results: Across 215 cases, the median follow-up was 3.17 years (1.49, 6.46). Females comprised 42.8% of cases. Age of presentation was neonatal (110, 51.2%) or presumed perinatal (105, 48.8%). The median age at diagnosis was 2.9 days (interquartile range, 2.0-9.9) for neonatal stroke and 12.9 months (interquartile range, 8.7-32.8) for presumed perinatal stroke. Strokes were classified as arterial (149, 69.3%), venous (60, 27.9%), both (4, 1.9%), or uncertain (2, 0.9%) by consensus imaging review. Of the 215 cases, there were 6 (2.8%) recurrent ischemic cerebrovascular events. Abnormal thrombophilia testing was not associated with recurrent stroke, except for a single patient with combined antithrombin deficiency and protein C deficiency. After excluding venous events, 155 patients were evaluated for arteriopathy and cardioembolic risk factors; neither was associated with recurrent stroke. Positive family history of thrombosis was not predictive of abnormal thrombophilia testing., Conclusions: Thrombophilia, arteriopathy, or cardioembolic risk factors were not predictive of recurrent events after perinatal stroke. Thrombophilia evaluation in perinatal stroke should only rarely be considered., (© 2017 American Heart Association, Inc.)

Cutaneovisceral angiomatosis with thrombocytopenia (CAT), also called multifocal lymphangioendotheliomatosis with thrombocytopenia (MLT), is a rare and newly described vascular malformation. Skin manifestations and thrombocytopenia are the hallmark of CAT/MLT, and visceral lesions are described. We report an infant with pulmonary hemorrhage, thrombocytopenia, and antiplatelet antibodies. There was no cutaneous involvement and the child was initially diagnosed with immune thrombocytopenia. Poor response to immune thrombocytopenia-directed therapy raised suspicion for an alternative diagnosis, and the ultimate diagnosis of CAT/MLT was made by lung tissue sampling. Unexpectedly, 2 years after resolution of pulmonary lesions and thrombocytopenia, the child developed typical cutaneous lesions.

Vascular anomalies can cause significant morbidity and mortality. Advances in diagnosis will be improved if noninvasive biomarkers can be identified, as obtaining a tissue biopsy can worsen the disease and precipitate complications. The goal of this study was to identify biomarkers for vascular anomaly patients to aid diagnosis and potentially give insights into pathogenesis. Blood was collected at baseline and then 6 and 12 months after treatment with the mTOR inhibitor sirolimus. Patients groups included generalized lymphatic anomaly (GLA), kaposiform lymphangiomatosis (KLA) and kaposiform hemangioendothelioma (KHE) with or without the Kasabach-Merritt phenomenon (KMP) coagulopathy. Serum was obtained from healthy controls selected to match the age and sex of the patients (21 days-28.5 years; 42% males; 58% females). Angiogenic and lymphangiogenic factors (VEGF-A, C, D, Ang-1 and Ang-2) were measured in serum using ELISA. In lymphatic anomaly patients, baseline levels of VEGF-A and VEGF-D were not different compared to controls. Angiopoietin-2 (Ang-2) levels were near controls levels in GLA patients but 10-fold greater in KLA patients and 14-fold greater in KHE patients when the KMP coagulopathy was present but not when it was absent. VEGF-C and angiopoietin-1 (Ang-1) levels were lower in KHE patients with KMP. Our analyses suggest that Ang-2 and Ang-1 can be used as biomarkers to help identify KLA and KHE patients with KMP coagulopathy with high sensitivity and specificity. After 12 months of sirolimus treatment, Ang-2 levels were lower in KLA and KHE with KMP patients compared to baseline levels and with most patients showing a clinical response. Hence, serum Ang-2 and Ang-1 levels may help in the diagnosis of patients with lymphatic anomalies and are concordant to sirolimus response.

We have entered an exciting era in the care of patients with vascular anomalies. These disorders require multidisciplinary care and coordination and dedicated centers have emerged to address this need. Vascular tumors have been treated with medical therapies for many years, while malformations have been historically treated with endovascular and operative procedures. The recent serendipitous discoveries of propranolol and sirolimus for vascular anomalies have revolutionized this field. In particular, sirolimus responses are challenging the dogma that vascular malformations are not biologically active. While initially explored for lymphatic anomalies, sirolimus is now being used broadly throughout the spectrum of vascular anomalies. Whether medical therapies are reserved for refractory patients or used first line is currently dependent on the experience and availability of alternative therapies at each institution. On the horizon, we anticipate new drugs targeting genes and pathways involved in vascular anomalies to be developed. Also, combinations of medications and protocols combining medical and procedural approaches are in development for refractory patients., (©2016 Frontline Medical Communications.)

Background: Kaposiform lymphangiomatosis is a rare, aggressive lymphatic disorder. The imaging and presenting features of kaposiform lymphangiomatosis can overlap with those of central conducting lymphatic anomaly and generalized lymphatic anomaly., Objective: To analyze the imaging findings of kaposiform lymphangiomatosis disorder and highlight features most suggestive of this diagnosis., Materials and Methods: We retrospectively identified and characterized 20 children and young adults with histopathological diagnosis of kaposiform lymphangiomatosis and radiologic imaging referred to the vascular anomalies center between 1995 and 2015., Results: The median age at onset was 6.5 years (range 3 months to 27 years). The most common presenting features were respiratory compromise (dyspnea, cough, chest pain; 55.5%), swelling/mass (25%), bleeding (15%) and fracture (5%). The thoracic cavity was involved in all patients; all patients had mediastinal involvement followed by lung parenchymal disease (90%) and pleural (85%) and pericardial (50%) effusions. The most common extra-thoracic sites of disease were the retroperitoneum (80%), bone (60%), abdominal viscera (55%) and muscles (45%). There was characteristic enhancing and infiltrative soft-tissue thickening in the mediastinum and retroperitoneum extending along the lymphatic distribution., Conclusion: Kaposiform lymphangiomatosis has overlapping imaging features with central conducting lymphatic anomaly and generalized lymphatic anomaly. Presence of mediastinal or retroperitoneal enhancing and infiltrative soft-tissue disease along the lymphatic distribution, hemorrhagic effusions and moderate thrombocytopenia (50-100,000/μl) should favor diagnosis of kaposiform lymphangiomatosis.

Background and Objectives: Complicated vascular anomalies have limited therapeutic options and cause significant morbidity and mortality. This Phase II trial enrolled patients with complicated vascular anomalies to determine the efficacy and safety of treatment with sirolimus for 12 courses; each course was defined as 28 days., Methods: Treatment consisted of a continuous dosing schedule of oral sirolimus starting at 0.8 mg/m(2) per dose twice daily, with pharmacokinetic-guided target serum trough levels of 10 to 15 ng/mL. The primary outcomes were responsiveness to sirolimus by the end of course 6 (evaluated according to functional impairment score, quality of life, and radiologic assessment) and the incidence of toxicities and/or infection-related deaths., Results: Sixty-one patients were enrolled; 57 patients were evaluable for efficacy at the end of course 6, and 53 were evaluable at the end of course 12. No patient had a complete response at the end of course 6 or 12 as anticipated. At the end of course 6, a total of 47 patients had a partial response, 3 patients had stable disease, and 7 patients had progressive disease. Two patients were taken off of study medicine secondary to persistent adverse effects. Grade 3 and higher toxicities attributable to sirolimus included blood/bone marrow toxicity in 27% of patients, gastrointestinal toxicity in 3%, and metabolic/laboratory toxicity in 3%. No toxicity-related deaths occurred., Conclusions: Sirolimus was efficacious and well tolerated in these study patients with complicated vascular anomalies. Clinical activity was reported in the majority of the disorders., (Copyright © 2016 by the American Academy of Pediatrics.)

Since publication of a single case report of lymphatic malformation improvement during sildenafil therapy for pulmonary hypertension, sildenafil use has propagated across multiple vascular anomalies diagnoses. Vascular anomalies are rare conditions, often with poor long-term outcomes from available therapies, making these patients vulnerable to novel therapy use. We have retrospectively reviewed 14 children with vascular anomalies treated with sildenafil. None of these patients reported improvement of disease while on treatment and some reported side effects including infections and bleeding. Pending more convincing prospective data, we recommend caution prior to sildenafil use for vascular anomalies., (© 2015 Wiley Periodicals, Inc.)

Objective: To review the presentation, management, and outcomes of Paget-Schroetter syndrome (PSS) in children and propose a multidisciplinary treatment algorithm involving pediatric and vascular surgery, interventional radiology, and hematology., Study Design: Patients with PSS presenting between 2003 and 2013 were reviewed. Demographics, symptoms, therapies, and functional outcomes were noted. Data from early patients informed the development of a multidisciplinary treatment algorithm applied to later patients., Results: Of 21 patients, mean ± SD age was 16 ± 1.6 years and 11 (52%) were male. Of patients with complete presentation data, common symptoms were edema (84%), discoloration (58%), and pain (58%). Thrombophilia workup revealed one heterozygote for factor V Leiden, 2 patients with factor VIII elevation and 1 patient with mildly low antithrombin. The most recent 8 patients were treated according to an algorithm developed by a multidisciplinary working group through experience with the first 13 cases. All patients underwent a venogram, endovascular intervention (including 15 receiving catheter-directed thrombolysis), and operative ipsilateral thoracic outlet decompression (first rib resection, anterior scalenectomy, and venolysis). Postoperative complications included hemothorax (2), pneumothorax (1), and recurrent thrombosis (2). Follow up duration was 12 ± 9.5 months. Symptoms recurred transiently in 1 patient., Conclusion: Pediatric patients with PSS can be treated successfully using a multidisciplinary treatment algorithm including anticoagulation, catheter-directed thrombolysis, and operative decompression of the thoracic outlet. Early outcomes are promising., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Objectives: To test the hypothesis that somatic phosphatidylinositol-4,5-bisphospate 3-kinase, catalytic subunit alpha (PIK3CA) mutations would be found in patients with more common disorders including isolated lymphatic malformation (LM) and Klippel-Trenaunay syndrome (KTS)., Study Design: We used next generation sequencing, droplet digital polymerase chain reaction, and single molecule molecular inversion probes to search for somatic PIK3CA mutations in affected tissue from patients seen at Boston Children's Hospital who had an isolated LM (n = 17), KTS (n = 21), fibro-adipose vascular anomaly (n = 8), or congenital lipomatous overgrowth with vascular, epidermal, and skeletal anomalies syndrome (n = 33), the disorder for which we first identified somatic PIK3CA mutations. We also screened 5 of the more common PIK3CA mutations in a second cohort of patients with LM (n = 31) from Seattle Children's Hospital., Results: Most individuals from Boston Children's Hospital who had isolated LM (16/17) or LM as part of a syndrome, such as KTS (19/21), fibro-adipose vascular anomaly (5/8), and congenital lipomatous overgrowth with vascular, epidermal, and skeletal anomalies syndrome (31/33) were somatic mosaic for PIK3CA mutations, with 5 specific PIK3CA mutations accounting for ∼ 80% of cases. Seventy-four percent of patients with LM from Seattle Children's Hospital also were somatic mosaic for 1 of 5 specific PIK3CA mutations. Many affected tissue specimens from both cohorts contained fewer than 10% mutant cells., Conclusions: Somatic PIK3CA mutations are the most common cause of isolated LMs and disorders in which LM is a component feature. Five PIK3CA mutations account for most cases. The search for causal mutations requires sampling of affected tissues and techniques that are capable of detecting low-level somatic mosaicism because the abundance of mutant cells in a malformed tissue can be low., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Objective: To characterize heparin-induced thrombocytopenia (HIT) at a single pediatric center including the prevalence and the accuracy of the 4Ts scoring system as a predictor of HIT., Study Design: In this retrospective cohort study, we identified 155 consecutive patients <21 years old with sufficient data for 4Ts scoring. The 4Ts scoring system is a validated pretest tool in adults that predicts the likelihood of HIT using clinical features. Hospital-wide exposure to unfractionated and low molecular weight heparin was determined by querying the hospital pharmacy database., Results: The majority of patients with suspected HIT (61.2%) were on surgical services. Prediction of HIT risk using initial 4Ts scoring found 3 (2%) had high risk 4Ts scores, 114 (73%) had intermediate risk 4Ts scores, and the remaining 38 (25%) had low risk 4Ts scores. HIT was confirmed in 0/38 patients with low risk 4Ts scores, 2/114 patients with intermediate-risk 4Ts scores, and all 3 patients with high-risk 4Ts scores presented with HIT with thrombosis. Of 12 positive HIT screening tests, results were falsely positive in 66.6% of patients with intermediate risk 4Ts scores and 100% of patients with low risk 4Ts scores. The prevalence of HIT was 0.058% and HIT with thrombosis was 0.046% in pediatric patients on unfractionated heparin., Conclusions: The prevalence of HIT appears significantly lower in pediatric patients compared with adults. Application of the 4Ts system as a pretest tool may reduce laboratory evaluation for HIT in heparin-exposed children with low risk 4Ts scores, decreasing unnecessary further testing, intervention, and cost., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Complex lymphatic anomalies include several diagnoses with overlapping patterns of clinical symptoms, anatomic location, imaging features, hematologic alterations, and complications. Lymphatic malformations likely arise through anomalous embryogenesis of the lymphatic system. Analysis of clinical, imaging, histologic, and hematologic features is often needed to reach a diagnosis. Aspiration of fluid collections can readily define fluid as chylous or not. The presence of chyle indicates dysfunction at the mesenteric or retroperitoneal level or above the cisterna chyli due to reflux. The imaging patterns of generalized lymphatic anomaly (GLA) and Gorham-Stout disease have been segregated with distinctive bone lesions and peri-osseous features. More aggressive histology (spindled lymphatic endothelial cells), clinical progression, hemorrhage, or moderate hematologic changes should raise suspicion for kaposiform lymphangiomatosis. Biopsy may be needed for diagnosis, though avoidance of rib biopsy is advised to prevent iatrogenic chronic pleural effusion. Lymphangiography can visualize the anatomy and function of the lymphatic system and may identify dysfunction of the thoracic duct in central conducting lymphatic anomalies. Local control and symptom relief are targeted by resection, laser therapy, and sclerotherapy. Emerging data suggest a role for medical therapies for complications of complex lymphatic anomalies. Outcomes include recurrent effusion, infection, pain, fracture, mortality, and rarely, malignancy. Complex lymphatic anomalies present significant diagnostic and therapeutic challenges. Results from a phase 2 study of sirolimus in these and other conditions are expected in 2014. Improved characterization of natural history, predictors of poor outcomes, responses to therapy, and further clinical trials are needed for complex lymphatic anomalies., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Objective: To describe the clinical and imaging characteristics of a new lymphatic disorder with a unique histological pattern and poor prognosis., Study Design: An observational, retrospective study identified and characterized 20 patients with distinct lymphatic histopathology referred to the Vascular Anomalies Center at Boston Children's Hospital between 1995 and 2011., Results: The median age at onset was 6.5 years (range, birth to 44 years). Clinical and radiologic findings suggested a generalized process. The most common presentations were respiratory symptoms (50%), hemostatic abnormalities (50%), and an enlarging, palpable mass (35%). All patients had mediastinal involvement; 19 patients developed pericardial (70%) and/or pleural effusions (85%). Extrathoracic disease manifested in bone and spleen and less frequently in abdominal viscera, peritoneum, integument, and extremities. Despite aggressive procedural and medical therapies, the 5-year survival was 51% and the overall survival was 34%. Mean interval between diagnosis and death was 2.75 years (range, 1-6.5 years)., Conclusions: We describe a clinicopathologically distinct lymphatic anomaly. We propose the term kaposiform lymphangiomatosis (KLA) because of characteristic clusters or sheets of spindled lymphatic endothelial cells accompanying malformed lymphatic channels. The intrathoracic component is most commonly implicated in morbidity and mortality; however, extrathoracic disease is frequent, indicating that KLA is not restricted to pulmonary lymphatics. The mortality rate of KLA is high despite aggressive multimodal therapy., (Copyright © 2014 Mosby, Inc. All rights reserved.)

Purpose: To determine the incidence of catheter-associated venous thromboembolic events (VTE) in long gap esophageal atresia (LGEA) patients treated at Boston Children's Hospital (BCH) and to identify possible risk factors associated with their development., Methods: We performed a retrospective analysis of LGEA patients from 2005 to 2012. Symptomatic VTEs with radiographic confirmation were defined as events. Potential risk factors were assessed by univariate analysis and multivariate logistic regression. Covariates included age, weight, initial gap length, cumulative days of pharmacologic paralysis and paralytic episodes, number and type of central venous catheters (CVCs), and number of operations., Results: Forty-four LGEA patients were identified. The incidence of CVC associated VTE was 34%. Univariate analysis identified age at Foker 1 (P=.03), paralysis duration (P=.01), episodes of paralysis (P=.001), cumulative number of CVC (P=.007) and length of stay (P=.03) as significant. Multivariate logistic regression identified the number of paralytic episodes as the only significant independent risk factor for VTE (P<.0001)., Conclusions: The incidence of symptomatic VTE was 34%, significantly higher than the VTE incidence of 4.5% reported for our other hospitalized children. These data have led to multidisciplinary discussions regarding thromboprophylaxis and development of a consensus-driven protocol. Since the initiation of this protocol, no VTEs have been identified., (© 2014.)

Background: The diagnosis and management of vascular anomalies of the extremities can be challenging as these disorders are uncommon and may clinically overlap. The aim of this paper is to describe the clinical, radiologic, and histopathologic features of fibro-adipose vascular anomaly (FAVA), a previously unrecognized disorder of the limb., Methods: The clinical, imaging, operative, and histopathologic data from patients with a unique intramuscular lesion of the extremities comprising dense fibrofatty tissue and slow-flow vascular malformations were retrospectively reviewed., Results: Sixteen patients diagnosed with FAVA of the extremity (3 male and 13 female individuals) met the clinical, radiologic, and histopathologic inclusion criteria. The age at presentation ranged from the time of birth to 28 years. The locations of the lesions were: calf (n=10), forearm/wrist (n=3), and thigh (n=3). Fourteen patients presented with severe pain. Seven of the patients with calf lesions had limited ankle dorsiflexion. On imaging, the complex intramuscular lesions replaced muscle fibers with fibrofatty overgrowth and phlebectasia (dilation of the veins). The extrafascial component comprised fatty overgrowth, phlebectasia, and an occasional lymphatic malformation. The histopathologic features comprised dense fibrous tissue, fat, and lymphoplasmacytic aggregates within atrophied skeletal muscle. Adipose tissue also infiltrated skeletal muscle at the periphery of the lesion. There were large, irregular, and sometimes excessively muscularized venous channels and smaller, clustered channels. Other findings include organizing thrombi, a lymphatic component, and dense fibrous tissue-encircled nerves., Conclusions: The constellation of clinical, radiologic, and histopathologic features constitutes a distinct entity comprising fibrofatty infiltration of muscle, unusual phlebectasia with pain, and contracture of the affected extremity. The clinical and radiologic findings permit the diagnosis of FAVA with major therapeutic implications., Level of Evidence: Level III.

Objectives: Pediatric inpatients with inflammatory bowel disease (IBD) are rarely considered for thromboprophylaxis because of concerns about safety and underappreciation of thrombotic risk. We characterized thromboembolism (TE) in children and young adults with inflammatory bowel disease (IBD) at a single tertiary care hospital., Methods: We performed a retrospective review of an inpatient billing database for all IBD admissions with colonic involvement and an anticoagulation database for thrombotic complications from 2006 to 2011., Results: Of 532 patients admitted with IBD with colonic involvement, 10 (1.9%) had TE (9 venous, 1 arterial), 2 of whom had recurrent thrombosis. Many of the events resulted in considerable morbidity, including 4 cerebrovascular events and 2 pulmonary emboli. Established risk factors in IBD colitis inpatients with TE included: indwelling catheter (4/10), first-degree family member with TE (2/10), hereditary thrombophilia (3/10), smoking (1/10), oral contraceptive (1/5 females), and thalidomide (1/10). Additionally, most (8/10) patients had acquired thrombophilia, mostly elevation of factor VIII and anticardiolipin antibodies. Patients with IBD and TE received therapeutic anticoagulation without significantly increased bleeding. Thrombus resolution was documented in 7 cases, persistence in 2 cases and recurrence in 2 cases., Conclusions: Pediatric inpatients hospitalized with IBD with colonic involvement have increased risk of TE, including complications of pulmonary embolism, recurrence, persistence, and indefinite long-term anticoagulation. Therapeutic anticoagulation in patients with IBD with active colitis appears safe. We identified both inherited thrombophilias and acquired risk factors in patients with IBD and TE. We presently use risk stratification and recommend prophylactic anticoagulation in high-risk patients.

Objective: To examine the presentation characteristics of patients with Kaposiform hemangioendothelioma (KHE) to describe the spectrum of disease and risk factors for Kasabach-Merritt phenomenon (KMP)., Study Design: A retrospective review of 163 patients referred to the Vascular Anomalies Center at Children's Hospital Boston for KHE between 1991 and 2009 identified 107 patients with sufficient data for inclusion., Results: The prevalence of KHE in Massachusetts is ∼0.91 case per 100000 children. KHE manifested in infancy in 93% of cases, with 60% as neonates. Common presenting features included enlarging cutaneous lesion (75%), thrombocytopenia (56%), and musculoskeletal pain or decreased function (23%). Cutaneous KHE favored the extremities, especially overlying joints. In our cohort, 71% developed KMP (11% after initial presentation), and 11% of patients lacked cutaneous findings. Retroperitoneal and intrathoracic lesions, though less common, were complicated by KMP in 85% and 100% of cases, respectively. Compared with superficial lesions, KHE infiltrating into muscle or deeper was 6.3-fold more likely to manifest KMP and 18-fold higher if retroperitoneal or intrathoracic. KHE limited to bone or presenting after infancy did not manifest KMP., Conclusion: An enlarging cutaneous lesion is the most common presenting feature of KHE in infancy. Older patients with KHE or those lacking cutaneous manifestations present with musculoskeletal complaints or atypical symptoms. The risk of KMP increases dramatically when tumor infiltrates muscle or when KHE arises in the retroperitoneum or mediastinum., (Copyright © 2013 Mosby, Inc. All rights reserved.)

Current methods for hypercoagulability panel testing require large blood volumes and long turn-around testing times. A novel microfluidic platform has been designed to perform automated multiplexed hypercoagulability panel testing at near patient, utilizing only a single droplet of blood sample. We test the hypothesis that this novel platform could be utilized to perform specific multiplexed ELISA-based hypercoagulability panel testing for antithrombin III, protein C, protein S and factor VIII antigens, as well as anticardiolipin/human anti-β2-glycoprotein-1 IgG antibodies--on blood samples. Sandwich ELISA was modified by utilizing magnetic beads coated with specific antibodies as the solid phase using fluorescence readout. Percentage recovery was calculated using four-parameter logistic curves. On-chip ELISA with single factors was compared with multiplex factor ELISA for known concentrations of sample. Blood samples were analyzed on-chip and compared with traditional bench-top assays. Time for multiplexed performance of hypercoagulability panel ELISA on-chip with controls is 72 min. Recovery rates (range 80-120%) for known concentrations of specific factors was not significantly different when assays were performed using a single factor vs. multiplex factor analysis. Assay results were not significantly different between individual assays performed either on bench-top or on-chip with patient blood and/or plasma. Utilizing a novel digital microfluidic platform, we demonstrate the feasibility of automated hypercoagulability panel testing on small volume of plasma and whole blood patient samples with high fidelity. Further investigation is required to test the application of this novel technology at point-of-care clinical settings.

Objective: The purpose of this article is to study the incidence, risk factors, and treatment of gross hemoglobinuria and oliguria following sclerotherapy for venous malformations., Materials and Methods: The clinical records and imaging studies of 131 patients with venous malformations (57 male and 74 female patients; age range, 2-58 years) who underwent sclerotherapy at our institution between July 1993 and August 2007 were reviewed. Demographic data, the location and estimated size of the malformation, the type and dose of the sclerosing agents, development of postprocedural hemoglobinuria and oliguria, and the treatment given were documented and analyzed., Results: Four hundred seventy-five sclerotherapy procedures were performed on 131 patients, with the number of procedures per patient ranging from 1 to 21 (mean, 3.6 procedures). Sodium tetradecyl sulfate was used in 47% of the procedures, ethanol in 27%, and both agents in 26%. Transient hemoglobinuria occurred after 34% of the sclerotherapy procedures, and 57% of these were associated with transient oliguria, with increased risk with higher adjusted doses (sclerosant volume/weight of patient) for both agents. Resolution of the hemoglobinuria and oliguria with hydration, alkalinization, and diuretics occurred in all patients. The risk of hemoglobinuria increased with higher adjusted dose (sclerosant volume/weight of patient) for both agents and with sclerotherapy of venous malformations affecting the lower extremities and multiple locations., Conclusion: Transient hemoglobinuria and oliguria are common complications of sclerotherapy for venous malformation. Nevertheless, with proper fluid management, all the patients promptly recovered. The risk correlates with the volume of sclerosant (adjusted to patient's weight) and is higher for lower extremity and multiple locations.

PTEN hamartoma tumor syndrome (PHTS) presents in a spectrum that encompasses the eponymous disorders Cowden and Bannayan-Riley-Ruvalcaba. Herein, we delineate the distinctive histopathology of a predominantly intramuscular lesion in PHTS, often called "arteriovenous malformation," because of certain imaging and histopathologic features. Cases were identified by review of lesions resected from patients with PHTS registered at our Vascular Anomalies Center and of unusual intramuscular vascular anomalies in our pathology database from 1985 to 2008. Thirty-four patients with this lesion were identified: 20 had a clinical diagnosis of, or were suspected to have, PHTS (genetically confirmed in 16). In 4 patients without clinical manifestations of PHTS, 2 had PTEN mutations, 1 did not, and in 1 the mutation was intronic. In the remaining 10, there was insufficient clinical information to fully assess whether they had manifestations of PHTS. Lesions manifested by 15 years of age, normally with pain and swelling, and were most often located in the lower extremity. The major mass was usually intramuscular, but often there were fascial and subcutaneous components and not infrequently a cutaneous vascular stain. Magnetic resonance imaging generally showed an infiltrative soft tissue lesion involving the muscle, fascia, and subcutis with frequently enlarged, serpiginous vessels, small arteriovenous fistulae with disproportionately dilated draining veins, and a prominent adipocytic component. Some lesions involved contiguous muscles, and 20% were multifocal. Resected specimens ranged in size from 1.2 to 25 cm; in 1 patient, amputation was necessary. Histopathologically, these unencapsulated masses, often with a nodular appearance at scanning magnification, consisted of: (1) a variable admixture of mature adipocytic and dense and/or myxoid fibrous tissues (50% to 90% of surface area); (2) a vascular component (10% to 50% of surface area) with: (a) clusters of venous channels, some with excessively and irregularly muscularized complex walls and lumens, and others with thin walls resembling pulmonary alveoli, (b) tortuous, thick-walled arteries with concentric muscular hyperplasia and relatively small lumens, (c) numerous small vessels (arteries, veins, and indeterminate channels), and (d) occasional arteriovenous communications; (3) lymphoid follicles (50%); (4) foci of bone (20%); and (5) hypertrophic nerves with "onion bulb" proliferation of periaxonal spindled cells (9%). We designate this disorganized overgrowth of essentially mesenchymal elements as PTEN hamartoma of soft tissue. It differs from other vascular and connective tissue lesions that occur in patients with PHTS. PTEN hamartoma of soft tissue is histopathologically distinctive, and its identification should prompt a thorough investigation for PHTS.

Blood microparticles are vesicular structures with a diameter of 100 to 1000 nm that are present in the blood of normal subjects and in patients with various diseases. These microparticles are derived from cells that circulate in the blood and cells associated with the blood vessel wall. Microparticle membranes retain the protein receptors of their parent cells and may retain RNAs and other cytosolic content. On the basis of surface protein expression, microparticles are known to be derived from platelets, granulocytes, monocytes, endothelial cells, smooth muscle cells, and tumor cells. Only a subpopulation of these microparticles expresses tissue factor.

Heightened publicity about hormonal contraception and thrombosis risk and the publication of new guidelines by the World Health Organization in 2009 and the Centers for Disease Control and Prevention in 2010 addressing this complex issue have led to multidisciplinary discussions on the special issues of adolescents cared for at our pediatric hospital. In this review of the literature and new guidelines, we have outlined our approach to the complex patients referred to our center. The relative risk of thrombosis on combined oral contraception is three- to fivefold, whereas the absolute risk for a healthy adolescent on this therapy is only 0.05% per year. This thrombotic risk is affected by estrogen dose, type of progestin, mechanism of delivery, and length of therapy. Oral progestin-only contraceptives and transdermal estradiol used for hormone replacement carry minimal or no thrombotic risk. Transdermal, vaginal, or intrauterine contraceptives and injectable progestins need further study. A personal history of thrombosis, persistent or inherited thrombophilia, and numerous lifestyle choices also influence thrombotic risk. In this summary of one hospital's approach to hormone therapies and thrombosis risk, we review relative-risk data and discuss the application of absolute risk to individual patient counseling. We outline our approach to challenging patients with a history of thrombosis, known thrombophilia, current anticoagulation, or family history of thrombosis or thrombophilia. Our multidisciplinary group has found that knowledge of the guidelines and individualized management plans have been particularly useful for informing discussions about hormonal and nonhormonal options across varied indications.