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Novel effective therapies are urgently needed in recurrent osteosarcoma. GD2 is expressed in human osteosarcoma tumours and cell lines. This study evaluated the disease control rate (DCR) in patients with recurrent osteosarcoma treated with the anti-GD2 antibody dinutuximab plus cytokine therapy as compared to historical outcomes.AOST1421 was a single-arm Phase 2 study for patients with recurrent pulmonary osteosarcoma in complete surgical remission. Patients received up to five cycles of dinutuximab (70 mg/mThirty-nine eligible patients were included in the outcome analysis. Dinutuximab did not demonstrate evidence of efficacy as 11/39 patients remained event free for a DCR of 28.2% (95% CI 15-44.9%). One of 136 administered therapy cycles met criteria for unacceptable toxicity when a patient experienced sudden death of unknown cause. Other ≥ Grade 3 toxicities included pain, diarrhoea, hypoxia, and hypotension. Pharmacokinetic parameters were similar in the two schedules.The combination of dinutuximab with GM-CSF did not significantly improve DCR in recurrent osteosarcoma. Dinutuximab toxicity and pharmacokinetics in adolescent and young adult osteosarcoma patients were similar to younger patients. Other strategies for targeting GD2 in osteosarcoma are being developed.

Context.— Molecular diagnostics play an increasing role in the diagnosis of Ewing sarcoma. The type of molecular testing used in clinical practice has been poorly described. Objective.— To describe patterns of translocation testing for newly diagnosed Ewing sarcoma. Design.— Children's Oncology Group (COG) trial AEWS1221 was a phase III randomized trial enrolling patients with newly diagnosed metastatic Ewing sarcoma from 2014 to 2019. Patients were required to have a histologic diagnosis of Ewing sarcoma, but translocation testing was not required. Sites provided types and results of any molecular diagnostics performed. Results.— Data from 305 enrolled patients were available. The most common type of molecular testing was fluorescence in situ hybridization (FISH) performed on the primary tumor (236 of 305 patients; 77.4%), with positive testing for an EWSR1 or FUS translocation in 211 (89.4%). Reverse transcription–polymerase chain reaction (RT-PCR) on the primary tumor was performed in 61 of 305 patients (20%), with positive results in 48 of 61 patients (78.7%). Next-generation sequencing was reported in 7 patients for the primary tumor and in 3 patients for metastatic sites. For all types of testing on either primary or metastatic tumor, 16 of 305 patients (5.2%) had no reported translocation testing. When evaluating all results from all testing, 44 of 305 patients (14.4%) lacked documentation of an abnormality consistent with a molecular diagnosis of Ewing sarcoma. Conclusions.— COG sites enrolling in a Ewing sarcoma trial have high rates of testing by FISH or PCR. A small proportion of patients have no translocation testing on either primary or metastatic sites. Next-generation sequencing techniques are not yet commonly used in this context.

Background Strategies to optimize management in rhabdomyosarcoma (RMS) include risk stratification to assign therapy aiming to minimize treatment morbidity yet improve outcomes. This analysis evaluated the relationship between complete metabolic response (CMR) as assessed by 18 F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET) imaging and event-free survival (EFS) in intermediate-risk (IR) and high-risk (HR) RMS patients. Methods FDG-PET imaging characteristics, including assessment of CMR and maximum standard uptake values (SUVmax) of the primary tumor, were evaluated by central review. Institutional reports of SUVmax were used when SUVmax values could not be determined by central review. One hundred and thirty IR and 105 HR patients had FDG-PET scans submitted for central review or had SUVmax data available from institutional report at any time point. A Cox proportional hazards regression model was used to evaluate the relationship between these parameters and EFS. Results SUVmax at study entry did not correlate with EFS for IR (p = 0.32) or HR (p = 0.86) patients. Compared to patients who did not achieve a CMR, EFS was not superior for IR patients who achieved a CMR at weeks 4 (p = 0.66) or 15 (p = 0.46), nor for HR patients who achieved CMR at week 6 (p = 0.75) or 19 (p = 0.28). Change in SUVmax at week 4 (p = 0.21) or 15 (p = 0.91) for IR patients or at week 6 (p = 0.75) or 19 (p = 0.61) for HR patients did not correlate with EFS. Conclusion Based on these data, FDG-PET does not appear to predict EFS in IR or HR-RMS. It remains to be determined whether FDG-PET has a role in predicting survival outcomes in other RMS subpopulations.

Children and adolescents with rhabdomyosarcoma (RMS) comprise a heterogeneous population with variable overall survival rates ranging between approximately 6% and 100% depending on defined risk factors. Although the risk stratification of patients has been refined across five decades of collaborative group studies, molecular prognostic biomarkers beyond FOXO1 fusion status have yet to be incorporated prospectively in upfront risk-based therapy assignments. This review describes the evolution of risk-based therapy and the current risk stratification, defines a new risk stratification incorporating novel biomarkers, and provides the rationale for the current and upcoming Children's Oncology Group RMS studies.

Pathogenic variants in the LRP2 gene, encoding the multiligand receptor megalin, cause a rare autosomal recessive syndrome: Donnai-Barrow/Facio-Oculo-Acoustico-Renal (DB/FOAR) syndrome. Because of the rarity of the syndrome, the long-term consequences of the tubulopathy on human renal health have been difficult to ascertain, and the human clinical condition has hitherto been characterized as a benign tubular condition with asymptomatic low-molecular-weight proteinuria. We investigated renal function and morphology in a murine model of DB/FOAR syndrome and in patients with DB/FOAR. We analyzed glomerular filtration rate in mice by FITC-inulin clearance and clinically characterized six families, including nine patients with DB/FOAR and nine family members. Urine samples from patients were analyzed by Western blot analysis and biopsy materials were analyzed by histology. In the mouse model, we used histological methods to assess nephrogenesis and postnatal renal structure and contrast-enhanced magnetic resonance imaging to assess glomerular number. In megalin-deficient mice, we found a lower glomerular filtration rate and an increase in the abundance of injury markers, such as kidney injury molecule-1 and N-acetyl-β-d-glucosaminidase. Renal injury was validated in patients, who presented with increased urinary kidney injury molecule-1, classical markers of chronic kidney disease, and glomerular proteinuria early in life. Megalin-deficient mice had normal nephrogenesis, but they had 19% fewer nephrons in early adulthood and an increased fraction of nephrons with disconnected glomerulotubular junction. In conclusion, megalin dysfunction, as present in DB/FOAR syndrome, confers an increased risk of progression into chronic kidney disease.

Background Strategies to optimize management in rhabdomyosarcoma (RMS) include risk stratification to assign therapy aiming to minimize treatment morbidity yet improve outcomes. This analysis evaluated the relationship between complete metabolic response (CMR) as assessed by 18F‐fluorodeoxyglucose positron emission tomography‐computed tomography (FDG‐PET) imaging and event‐free survival (EFS) in intermediate‐risk (IR) and high‐risk (HR) RMS patients. Methods FDG‐PET imaging characteristics, including assessment of CMR and maximum standard uptake values (SUVmax) of the primary tumor, were evaluated by central review. Institutional reports of SUVmax were used when SUVmax values could not be determined by central review. One hundred and thirty IR and 105 HR patients had FDG‐PET scans submitted for central review or had SUVmax data available from institutional report at any time point. A Cox proportional hazards regression model was used to evaluate the relationship between these parameters and EFS. Results SUVmax at study entry did not correlate with EFS for IR (p = 0.32) or HR (p = 0.86) patients. Compared to patients who did not achieve a CMR, EFS was not superior for IR patients who achieved a CMR at weeks 4 (p = 0.66) or 15 (p = 0.46), nor for HR patients who achieved CMR at week 6 (p = 0.75) or 19 (p = 0.28). Change in SUVmax at week 4 (p = 0.21) or 15 (p = 0.91) for IR patients or at week 6 (p = 0.75) or 19 (p = 0.61) for HR patients did not correlate with EFS. Conclusion Based on these data, FDG‐PET does not appear to predict EFS in IR or HR‐RMS. It remains to be determined whether FDG‐PET has a role in predicting survival outcomes in other RMS subpopulations., This analysis evaluated the relationship between complete metabolic response (CMR) as assessed by 18F‐fluorodeoxyglucose positron emission tomography‐computed tomography (FDG‐PET) imaging and event‐free survival (EFS) in intermediate‐risk (IR) and high‐risk (HR) RMS patients. FDG‐PET parameters including baseline SUVmax, change in SUVmax, and CMR do not predict EFS in IR or HR‐RMS.

Background Established prognostic indicators in rhabdomyosarcoma (RMS), the most common childhood soft tissue sarcoma, include several clinicopathologic features. Among pathologic features, anaplasia has been suggested as a potential prognostic indicator, but the clinical significance of anaplasia remains unclear. Methods Patients enrolled on one of five recent Children's Oncology Group clinical trials for RMS (D9602, n = 357; D9802, n = 80; D9803, n = 462; ARST0331, n = 335; and ARST0531, n = 414) with prospective central pathology review were included in this study. Clinicopathologic variables including demographic information, risk group, histologic subtype, and anaplasia were recorded along with overall survival (OS) and failure-free survival (FFS) with failure defined by recurrence, progression, or death. The log-rank test was used to compare OS and FFS. Results Anaplasia was more common in embryonal RMS (27% of all embryonal RMS) than other subtypes of RMS (11% for alveolar RMS, 7% for botryoid RMS, 11% for spindle cell RMS). On multivariate analyses, anaplasia was not an independent prognostic factor in RMS (OS:hazard ratio (HR) = 1.12, p = 0.43; FFS:HR = 1.07, p = 0.56) across all subtypes or within embryonal RMS only (OS:HR = 1.41, p = 0.078; FFS:HR = 1.25, p = 0.16). Among tumors with TP53 mutations, 69% had anaplasia, while only 24% of tumors with anaplasia had a tumoral TP53 mutation. Conclusions Anaplasia is not an independent indicator of adverse outcomes in RMS. Emerging information on the prognostic significance of TP53 mutations raises the possibility that anaplasia may be a surrogate marker of TP53 mutations in some cases. Tumoral TP53 mutation status may be investigated as a prognostic indicator in future studies.

Background The outcome for patients with metastatic rhabdomyosarcoma (RMS) remains poor. A previous Children's Oncology Group (COG) study (ARST0431) for patients with metastatic RMS produced no improvement in outcome using multiple cytotoxic agents in a dose-intensive manner. The authors report results from the subsequent COG study (ARST08P1), which evaluated the feasibility and efficacy of adding cixutumumab (insulin-like growth factor-1 monoclonal antibody) or temozolomide to the ARST0431 intensive chemotherapy backbone. Methods Two nonrandomized pilot studies were conducted in patients with metastatic RMS, initially to determine feasibility, and both pilots were expanded to assess efficacy. All patients received 54 weeks of chemotherapy, including vincristine/irinotecan, interval-compressed vincristine/doxorubicin/cyclophosphamide alternating with ifosfamide/etoposide, and vincristine/dactinomycin/cyclophosphamide. In pilot 1, patients received intravenous cixutumumab (3, 6, or 9 mg/kg) once weekly throughout therapy. In pilot 2, patients received oral temozolomide (100 mg/m2 ) daily for 5 days with irinotecan. All patients received radiation to the primary tumor and to metastatic sites. Results One hundred sixty-eight eligible patients were enrolled (97 on pilot 1 and 71 on pilot 2). Most patients were aged ≥10 years (73%), with alveolar histology (70%), and had bone and/or bone marrow metastases (59%). Toxicities observed in each pilot were similar to those reported on ARST0431. With a median follow-up of 2.9 years, the 3-year event-free survival rate was 16% (95% confidence interval, 7%-25%) with cixutumumab and 18% (95% confidence interval, 2%-35%) with temozolomide. Conclusions The addition of cixutumumab or temozolomide to intensive multiagent chemotherapy for metastatic RMS was safe and feasible. Neither agent improved outcome compared with the same chemotherapy that was used on ARST0431.

Gaucher disease is a hereditary lipid storage disorder that affects the enzyme beta glucocerebrosidase, causing accumulation of glucocerebroside in macrophages of the reticuloendothelial system. Accumulation can occur in the liver and spleen, manifesting as hepatosplenomegaly, as well as within the bone marrow. Hepatic involvement is usually diffuse but can occasionally manifest as focal liver lesions. We present a case of a 2-year-old boy with Gaucher disease and an infiltrating liver lesion detected on imaging, which was pathologically shown to be focal changes related to the disease. Imaging characteristics of this lesion using hepatocyte specific contrast agent enhanced MRI, which have not been previously discussed in the literature, are described.

A subset of poorly differentiated squamous cell carcinomas, NUT midline carcinomas (NMC) are characterized by a translocation t(15;19)(q13;p13) [ 1 ]. The prognosis is generally dismal [ 2 ] and therapeutic success has been limited to exceptional cases [ 3 ]. We present two cases of pediatric NMC from two different institutions treated according to a multimodal sarcoma approach involving surgery, chemotherapy, and focal radiotherapy. One patient has remained in complete continuous remission for over 6 years, while the other is in CR in early follow-up off therapy. Our proposed multimodal strategy apparently meets the aggressive biologic nature of NMC and should be considered for further evaluation in this context potentially in the setting of a clinical trial.

A pediatric cytopathology symposium was held at the recent 20th International Congress of Cytology, which convened in Sydney, Australia, in May 2019. This educational event brought together cytopathologists from different countries and different institutions to discuss some of the practical considerations when applying current diagnostic classification systems to cytopathology specimens from young (pediatric and adolescent) patients. Within the past decade, various classification systems have been developed to create more standardized terminology for cytopathology specimen reporting among institutions, which can lead to improved management guidelines based on evidence-based medicine. It is well known that a majority of the peer-reviewed publications in cytopathology discussing the usefulness of these classification schemes predominantly contain case cohorts of adult patients. Although pediatric cases are not excluded from following these diagnostic guidelines, there is less of an emphasis on this age group with respect to unique findings and management differences. Thus, discussing the role of these guidelines and their applications in pediatric cases at an international educational gathering can not only be beneficial in educating the cytopathology community about the value of applying these classification systems to pediatric populations, but also can raise awareness of unique entities in cytologic specimens obtained from young patients.

Background The prognostic value of histologic response for osteosarcoma may have changed with induction chemotherapy schedules over time. We hypothesized that the increased intensity of induction therapy provided on INT0133 compared to the Children's Cancer Group study CCG-782 would diminish the impact of histologic response on the risk of events after definitive surgery. Methods Retrospective analysis was performed for patients aged

Background Complete surgical resection of primary tumors is critical for long-term control of high-grade osteosarcoma. Uniform assessment of the extent of surgical resection is important in clinical trials, though the accuracy of this reporting has been poorly studied. Methods We conducted a retrospective cohort study of patients 5–40 years of age with newly diagnosed high-grade resectable osteosarcoma treated as part of the AOST0331 clinical trial at Children's Oncology Group institutions. The extent of surgical resection of the primary tumor was graded as wide or radical by the treating institution. Central assessment of the extent of resection by two orthopedic oncologists was compared with institutional assessment by reviewing pathology and operative reports. Results We included 956 patients who had data available for central review. The extent of resection reported by treating institutions was 536/956 (56%) radical and 420/956 (44%) wide. The extent of resection assessed by central review was 162/956 (17%) radical and 794/956 (83%) wide. The overall discordance rate for the cohort was 43%. Conclusions Institutional reports of radical resection in high-grade osteosarcoma significantly over-estimate the proportion of patients undergoing radical resection. This highlights the need for centralized review and improved accuracy of reporting of the extent of resection. J. Surg. Oncol. 2016;113:351–354. © 2016 Wiley Periodicals, Inc.

Background Distinguishing alveolar rhabdomyosarcoma (ARMS) from embryonal rhabdomyosarcoma (ERMS) is of prognostic and therapeutic importance. Criteria for classifying these entities evolved significantly from 1995 to 2013. ARMS is associated with inferior outcome; therefore, patients with alveolar histology have generally been excluded from low-risk therapy. However, patients with ARMS and low-risk stage and group (Stage 1, Group I/II/orbit III; or Stage 2/3, Group I/II) were eligible for the Children's Oncology Group (COG) low-risk rhabdomyosarcoma (RMS) study D9602 from 1997 to 1999. The characteristics and outcomes of these patients have not been previously reported, and the histology of these cases has not been reviewed using current criteria. Procedure We re-reviewed cases that were classified as ARMS on D9602 using current histologic criteria, determined PAX3/PAX7-FOXO1 fusion status, and compared these data with outcome for this unique group of patients. Results Thirty-eight patients with ARMS were enrolled onto D9602. Only one-third of cases with slides available for re-review (11/33) remained classified as ARMS by current histologic criteria. Most cases were reclassified as ERMS (17/33, 51.5%). Cases that remained classified as ARMS were typically fusion-positive (8/11, 73%), therefore current classification results in a similar rate of fusion-positive ARMS for all clinical risk groups. In conjunction with data from COG intermediate-risk treatment protocol D9803, our data demonstrate excellent outcomes for fusion-negative ARMS with otherwise low-risk clinical features. Conclusions Patients with fusion-positive RMS with low-risk clinical features should be classified and treated as intermediate risk, while patients with fusion-negative ARMS could be appropriately treated with reduced intensity therapy.

Osteosarcoma (OS) is the most common malignant bone tumor of children and young adults. Although the optimization of combination chemotherapy has led to significantly improved prognosis, survival remains poor for patients with recurrent tumor or metastatic disease at diagnosis. The international TARGET (Therapeutically Applicable Research to Generate Effective Therapy) OS project team collected 285 clinically annotated samples (age Citation Format: Paul S. Meltzer, Sean Davis, Jack Zhu, Yonghong Wang, Sven Bilke, Joshua Waterfall, Robert Walker, Marbin Pineda, Yuan Jiang, Sharon Savage, Lisa Mirabello, Tsz-Kwong Man, Aaron Taylor, Monika J. Sun, Jay Wunder, Irene Andrulis, Nalan Gokgoz, Shintaro Iwata, Miki Ohira, Mark Krailo, Don Barkauskas, Lisa Teot, Timothy Triche, Silvia de Toledo, Antonio S. Petrilli, Jaime M. Guidry Auvil, Richard Gorlick, Malcolm A. Smith, Daniela Gerhard, Ching C. Lau. Translational and mechanistic implications of osteosarcoma genomics: A TARGET report [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-307.

Purpose Intermediate-risk rhabdomyosarcoma (RMS) includes patients with either nonmetastatic, unresected embryonal RMS (ERMS) with an unfavorable primary site or nonmetastatic alveolar RMS (ARMS). The primary aim of this study was to improve the outcome of patients with intermediate-risk RMS by substituting vincristine and irinotecan (VI) for half of vincristine, dactinomycin, and cyclophosphamide (VAC) courses. All patients received a lower dose of cyclophosphamide and earlier radiation therapy than in previous trials. Patients and Methods Patients were randomly assigned at study entry to either VAC (cumulative cyclophosphamide dose, 16.8 g/m2) or VAC/VI (cumulative cyclophosphamide dose, 8.4 g/m2) for 42 weeks of therapy. Radiation therapy started at week 4, with individualized local control plans permitted for patients younger than 24 months. The primary study end point was event-free survival (EFS). The study design had an 80% power (5% one-sided α-level) to detect an improved long-term EFS from 65% (with VAC) to 76% (with VAC/VI). Results A total of 448 eligible patients were enrolled in the study. At a median follow-up of 4.8 years, the 4-year EFS was 63% with VAC and 59% with VAC/VI ( P = .51), and 4-year overall survival was 73% for VAC and 72% for VAC/VI ( P = .80). Within the ARMS and ERMS subgroups, no difference in outcome by treatment arm was found. Severe hematologic toxicity was less common with VAC/VI therapy. Conclusion The addition of VI to VAC did not improve EFS or OS for patients with intermediate-risk RMS. VAC/VI had less hematologic toxicity and a lower cumulative cyclophosphamide dose, making VAC/VI an alternative standard therapy for intermediate-risk RMS.

Context.—Cerebrospinal fluid cytology is a critical diagnostic tool for the diagnosis of many conditions affecting the central nervous system.Objective.—To assess the performance characteristics of cerebrospinal fluid cytology samples by evaluating participant interpretations within the College of American Pathologists Nongynecologic Cytopathology Education program.Design.—Participant interpretations (N = 46 264) evaluated in the College of American Pathologists Nongynecologic Cytopathology Education Program were examined for concordance with the general category and with the reference diagnosis. Two nonlinear mixed models were used to analyze the concordance rates.Results.—The overall concordance rates for the general category and reference diagnosis were 92.1% and 81.0%, respectively. In the malignant category, the concordance rates with the reference diagnosis were lowest for diagnoses of nonhematopoietic small blue round cell tumors (54.8%) and metastatic malignancy (77.5%); the concordance rate with the reference diagnosis was highest for leukemia/lymphoma (94.0%). In the benign category, the concordance rate was lowest for normal cerebrospinal fluid reference diagnoses (58.6%), followed by acute and chronic inflammation (64.6%), fungal infection (80.8%), and macrophages (85.3%). Significant differences in concordance were uncovered when performance was evaluated by participant type and stain technique. Leukemia/lymphoma was the most common diagnosis for misclassified nonhematopoietic small blue round cell tumor cases and negative or inflammatory cerebrospinal fluid cases.Conclusions.—This study illustrates the difficulties in achieving accurate diagnoses from cerebrospinal fluid specimens, particularly for nonhematopoietic small blue round cell tumors and normal and inflammatory cerebrospinal fluid specimens.

Non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) is an indolent thyroid tumor characterized by frequent RAS mutations and an absence of the BRAF V600E mutation commonly seen in classical papillary thyroid carcinoma (cPTC). The ability to differentiate potential NIFTP/follicular variant of papillary thyroid carcinoma (FVPTC) from cPTC at the time of fine-needle aspiration (FNA) can facilitate conservative management of NIFTP. The aim of the current study was to investigate how molecular testing may add to cytologic assessment in the pre-operative differentiation of potential NIFTP/FVPTC and cPTC. We had previously evaluated cytologists' ability to prospectively distinguish potential NIFTP/FVPTC from cPTC in a cohort of 56 consecutive FNAs diagnosed as malignant or suspicious for malignancy. We utilized this cohort to perform molecular analysis. Detected molecular abnormalities were stratified into two groups: (1) those supporting malignancy and (2) those supporting a diagnosis of potential NIFTP/FVPTC. The cytologists' characterization of cases and the detected molecular alterations were correlated with the final histologic diagnoses. Molecular testing was performed in 52 (93%) of the 56 cases. For the 37 cases cytologists favored to be cPTC, 31 (84%) had a molecular result that supported malignancy (28 BRAF V600E mutations, 2 NTRK1 fusions, 1 AGK-BRAF fusion). For the 8 cases that were favored to be NIFTP/FVPTC by cytologists, 7 (88%) had a molecular result that supported conservative management (1 NRAS mutation, 6 wild-type result). Seven cases were designated as cytomorphologically indeterminate for NIFTP/FVPTC or cPTC, of which 6 (86%) had a molecular result that would have aided in the pre-operative assessment of potential NIFTP/FVPTC or cPTC/malignancy. These included 3 BRAF V600E mutations in nodules that were cPTC on resection, an HRAS mutation, and a wild-type result in the 2 nodules that were NIFTP, and a TERT promoter mutation along with an NRAS mutation in a poorly differentiated thyroid carcinoma. For nodules with an FNA diagnosis of suspicious for malignancy or malignant, cytologists can differentiate most cases of potential NIFTP/FVPTC from cPTC. However, molecular testing may be valuable for a subset of cases, especially those that are indeterminate for potential NIFTP/FVPTC versus cPTC based on cytologic features alone.

Background Although chemotherapy has improved outcome of osteosarcoma, 30–40% of patients succumb to this disease. Survivors experience substantial morbidity and mortality from anthracycline-induced cardiotoxicity. We hypothesized that the cardioprotectant dexrazoxane would 1) support escalation of the cumulative doxorubicin dose (600 mg/m2) and 2) not interfere with the cytotoxicity of chemotherapy measured by necrosis grading in comparison to historical control data.9

Microvillus inclusion disease (MVID) is a rare congenital disorder that manifests early in infancy as intractable watery diarrhea. The entity is characterized morphologically by a deficient brush border and apical cytoplasmic inclusions within absorptive cells (enterocytes) due to misplaced assembly of brush border proteins. The diagnosis is based upon histopathology, special stains, immunohistochemistry (IHC), and ultimately upon electron microscopy. Currently, the periodic acid-Schiff stain (PAS) and CD10 IHC are commonly used as adjuncts, but in addition to brush border structures, they stain a variety of apical cytoplasmic inclusions and organelles, thereby interfering with recognition of microvillus inclusions. Villin is a protein that specifically binds to the actin core bundle of microvilli. We utilized villin IHC in formalin-fixed paraffin-embedded gastrointestinal biopsies from 6 patients with MVID, 5 with celiac disease, and 17 children with normal intestinal biopsies and compared the results with those obtained with CD10 IHC and PAS staining. All MVID cases had confirmatory electron microscopy at the time of diagnosis. Villin immunoreactivity was restricted to the brush border in the control groups. In MVID, villin IHC showed attenuation or loss of the surface brush border and also highlighted the cytoplasmic microvillus inclusions with clarity. In MVID, CD10 IHC and the PAS stain also showed attenuation or loss of the surface brush border, but staining of a variety of cytoplasmic structures largely obscured the microvillus inclusions. In sum, villin IHC is a reliable and superior adjunct in the diagnosis of MVID. Study of additional cases will determine whether villin IHC would obviate the need for electron microscopic confirmation.

Hepatobiliary and pancreatic mass lesions, which may be infectious, inflammatory, or neoplastic in origin, are uncommon in pediatric patients. When they are identified, the diagnostic considerations vary from those in adults, reflecting important differences in the types of tumors seen in these two populations. Although they account for a minority of cases, some inborn errors of metabolism, such as tyrosinemia, and other genetic syndromes, particularly Von Hippel-Lindau (VHL) and Beckwith-Wiedemann, predispose affected individuals to developing hepatic or pancreatic tumors as infants, children, or adolescents. Moreover, the prognostic implications of some tumors differ based on age; for example, pancreatoblastoma has a better prognosis in children than in adults. Most of the mass lesions detected in these anatomic locations undergo imaging studies to evaluate features such as size, number (single or multiple), extent, character (homogeneous or heterogeneous, solid or cystic), the presence or absence of necrosis, and vascularity and to define better those patients for whom a pathological diagnosis is needed prior to further treatment. Specimens can be acquired by percutaneous image-guided biopsy of hepatic and pancreatic masses, or by endoscopy for pancreatobiliary lesions, and include aspirates, small biopsies, and brushings. This chapter will review the main lesions to consider in a pediatric patient presenting with a hepatic, biliary, or pancreatic mass and the morphologic features and ancillary studies that are useful for reaching a definitive or narrowed differential diagnosis and guiding patient care.

GM2 activator (GM2A) deficiency (OMIM 613109) is a rare lysosomal storage disorder, with onset typically in infancy or early childhood. Clinically, it is almost indistinguishable from Tay-Sachs disease (OMIM 272800) or Sandhoff disease (OMIM 268800); however, traditionally available biochemical screening tests will most likely reveal normal results. We report a 2-year-old male with initially normal development until the age of 9 months, when he presented with developmental delay and regression. Workup at that time was unrevealing; at 15 months, he had abnormal brain MRI findings and a cherry red spot on ophthalmological examination. Family history and all laboratory studies were uninformative. The combination of a cherry red spot and developmental regression was strongly suggestive of a lysosomal storage disorder. Sequence analysis of GM2A did not reveal any pathogenic variants; however, exon 2 of GM2A could not be amplified by PCR, raising suspicion for a large, homozygous deletion. Subsequent copy number analysis confirmed a homozygous deletion of exon 2 in GM2A. This is the first reported case of GM2A deficiency being caused by a whole exon deletion. We describe previously unreported electron microscopy findings in this disease, thus expanding the clinical and variant spectrum for GM2 activator deficiency. These findings demonstrate the increased degree of suspicion required for diagnosis of this rare disorder. Brief Summary: This case of GM2 activator deficiency was caused by a homozygous deletion in GM2A, demonstrating the need to include exon level copy number analysis in any workup to fully exclude this disorder.

The performance of fine needle aspiration (FNAs) in children and adolescents involves special considerations and challenges that are infrequently encountered with adult patients. In particular, FNAs in pediatric patients require obtaining consent from the parent or legal guardian, and in some instances, patients must be restrained, sedated, or anesthetized during the procedure. As in adults, optimally prepared cytologic specimens, including aspirate smears and squash and touch preparations, are helpful for intraoperative or intraprocedural evaluation of pediatric lesions in order to ensure appropriate triaging of the sample. This is particularly important given the overlapping morphological features of many pediatric lesions and consequent need for ancillary studies to reach an accurate and specific diagnosis. This chapter will focus on how we approach pediatric FNAs, and offer comparisons to adult cytopathology.

A wide variety of bone and soft tissue lesions are seen in the pediatric population, including benign and malignant neoplasms, as well non-neoplastic processes. Fine needle aspiration and/or small biopsies are increasingly used for evaluating these lesions and in many cases, allow definitive diagnosis or a narrowed differential diagnosis on which to base treatment. This chapter describes the cytologic features of a number of common and uncommon neoplastic and non-neoplastic lesions of bone and soft tissue seen in the pediatric population, as well as key clinical and radiographic features of those entities and differential diagnostic considerations.

The 22q11 deletion syndrome (22q11DS) is the most common microdeletion syndrome in humans and one of the chromosomal conditions most associated with psychosis and autism spectrum disorder. To date, only 2 neuropathologic studies of 22q11DS have been reported. Findings included polymicrogyria, neuronal heterotopias, excess subcortical white-matter (interstitial) neurons, significant white-matter gliosis/hypomyelination, and microvasculopathy. Here, we report on a 3-month-old infant with documented 22q11DS, tetralogy of Fallot, and pulmonary atresia. The brain exhibited tortuous cerebral vessels and proportionately smaller occipital lobes. Histologic examination revealed cerebral white-matter pathology and subtle differences in cortical lamination, including an excess of interstitial white-matter neurons compared with a sample of age-matched controls. There was a 15% increase in DARPP-32+ medium spiny neurons in the anterior-superior caudate. In this first neuropathologic report of an infant with 22q11DS, the findings were similar to previously reported manifestations and are likely secondary to perfusion issues, developmental microvasculopathy, and abnormal frontal cortical development.

Classical (or isolated) methylmalonic acidemia (MMA) is a heterogeneous inborn error of metabolism most typically caused by mutations in the vitamin B12-dependent enzyme methylmalonyl-CoA mutase (MUT). With the improved survival of individuals with MMA, chronic kidney disease has become recognized as part of the disorder. The precise description of renal pathology in MMA remains uncertain.Light microscopy, histochemical, and ultrastructural studies were performed on the native kidney obtained from a 19-year-old patient with mut MMA who developed end stage renal disease and underwent a combined liver-kidney transplantation.The light microscopy study of the renal parenchyma in the MMA kidney revealed extensive interstitial fibrosis, chronic inflammation, and tubular atrophy. Intact proximal tubules were distinguished by the widespread formation of large, circular, pale mitochondria with diminished cristae. Histochemical preparations showed a reduction of cytochrome c oxidase and NADH activities, and the electron microscopy analysis demonstrated loss of cytochrome c enzyme activity in these enlarged mitochondria.Our results demonstrate that the renal pathology of MMA is characterized by megamitochondria formation in the proximal tubules in concert with electron transport chain dysfunction. Our findings suggest therapies that target mitochondrial function as a treatment for the chronic kidney disease of MMA.

Pediatric rhabdomyosarcoma (RMS) is traditionally classified on the basis of the histologic appearance into alveolar (ARMS) and embryonal (ERMS) subtypes. The majority of ARMS contain a PAX3-FOXO1 or PAX7-FOXO1 gene fusion, but about 20% do not. Intergroup Rhabdomyosarcoma Study stage-matched and group-matched ARMS typically behaves more aggressively than ERMS, but recent studies have shown that it is, in fact, the fusion status that drives the outcome for RMS. Gene expression microarray data indicate that several genes discriminate between fusion-positive and fusion-negative RMS with high specificity. Using tissue microarrays containing a series of both ARMS and ERMS, we identified a panel of 4 immunohistochemical markers-myogenin, AP2β, NOS-1, and HMGA2-which can be used as surrogate markers of fusion status in RMS. These antibodies provide an alternative to molecular methods for identification of fusion-positive RMS, particularly in cases in which there is scant or poor-quality material. In addition, these antibodies may be useful in fusion-negative ARMS as an indicator that a variant gene fusion may be present.

Pediatric malignancies are uncommon and many have overlapping morphologic features, which together present diagnostic challenges. Cytopathology is recognized as an accurate and cost-effective modality for the diagnosis of pediatric malignancies in resource-limited countries, but is underused for this purpose in the United States. This review focuses on the cytopathology of pediatric malignancies with the goal of demystifying cytologic diagnoses of these entities. Differences between malignancies in young patients and adults are discussed, and key epidemiological features of childhood malignancies are highlighted. In addition, the use of cytopathology in different geographical settings is contrasted to illustrate the impact of variable usage on the incidence of malignancy and the types of tumors observed in cytologic specimens. A review of the pattern-based approach to differential diagnosis is also incorporated, including the cytomorphologic features and ancillary studies that help to distinguish between various malignancies within each pattern. Cancer (Cancer Cytopathol) 2014;122:322-36. V C 2014 American Cancer Society.

Combined oxidative phosphorylation deficiency type 7 (COXPD7) is a rare disorder of mitochondrial metabolism that results in optic atrophy and Leigh syndrome-like disease. We describe 2 siblings with compound heterozygous mutations in the recently identified C12orf65 gene who presented with optic atrophy and mild developmental delays and subsequently developed bilateral, symmetric lesions in the brainstem reminiscent of Leigh syndrome. Repeat neuroimaging demonstrated reversibility of the findings in 1 sibling and persistent metabolic stroke in the other. This article highlights the phenotypic manifestations from a novel mutation in the C12orf65 gene and reviews the clinical presentation of the 5 other individuals reported to date who carry mutations in this gene.

In mice, activated Hedgehog (Hh) signaling induces tumors with myogenic differentiation. In humans, hyperactive Hh signaling due to germline PATCHED1 (PTCH1) mutations has been linked to nevoid basal cell carcinoma syndrome (NBCCS). We report an embryonal rhabdomyosarcoma in a 16-month-old girl with NBCCS and review the literature on myogenic neoplasms in NBCCS, including 8 fetal rhabdomyomas and 3 rhabdomyosarcomas. Of note, 3 population studies, including 255 individuals with NBCCS aged 4 months to 87 years, did not identify any myogenic tumors. Thus, myogenic tumors in NBCCS are rare and include both rhabdomyosarcomas and fetal rhabdomyomas.

BACKGROUND Rhabdomyosarcoma (RMS) represents a diverse category of myogenic malignancies with marked differences in molecular alterations and histology. This study examines the question if RMS predisposition due to germline TP53 mutations correlates with certain RMS histologies. METHODS The histology of RMS tumors diagnosed in 8 consecutive children with TP53 germline mutations was reviewed retrospectively. In addition, germline TP53 mutation analysis was performed in 7 children with anaplastic RMS (anRMS) and previously unknown TP53 status. RESULTS RMS tumors diagnosed in 11 TP53 germline mutation carriers all exhibited nonalveolar, anaplastic histology as evidenced by the presence of enlarged hyperchromatic nuclei with or without atypical mitotic figures. Anaplastic RMS was the first malignant diagnosis for all TP53 germline mutation carriers in this cohort, and median age at diagnosis was 40 months (mean, 40 months ± 15 months; range, 19-67 months). The overall frequency of TP53 germline mutations was 73% (11 of 15 children) in pediatric patients with anRMS. The frequency of TP53 germline mutations in children with anRMS was 100% (5 of 5 children) for those with a family cancer history consistent with Li-Fraumeni syndrome (LFS), and 80% (4 of 5 children) for those without an LFS cancer phenotype. CONCLUSIONS Individuals harboring germline TP53 mutations are predisposed to develop anRMS at a young age. If future studies in larger anRMS cohorts confirm the findings of this study, the current Chompret criteria for LFS should be extended to include children with anRMS irrespective of family history. Cancer 2014;120:1068–1075. © 2013 American Cancer Society.

To determine the minimum survival time for detection of antemortem myocardial ischaemia with postmortem imaging (PMI) techniques.Nine pigs underwent ligation of the left anterior descending (LAD) (8) and/or right coronary artery (RCA) branch (4), and were killed 30 min-6 h after ligation. PMI (MRI and CT angiography) was performed 2-55 h after euthanasia. Signal intensity of myocardial segments was measured. The hearts were removed, the coronary arteries injected to mark perfused segments, and sections submitted for histology.MRI T2-weighted sequences showed the ischaemic area as hyperintense in 4/4 LAD ligations with ≥4 h of ischaemia but in 0/4 with4 h. Histological evidence of ischaemia was present in 4/4 animals after 4 h. Right ventricular ischaemic myocardium was visible on MRI T2-weighted sequences after 6 h of ischaemia in one animal. CT angiography showed the occluded coronary artery in all cases.Ischaemic lesions of the left ventricle, but not of the right, at least 4 h old can be detected as hyperintense areas on T2-weighted postmortem MRI. This technique is most sensitive in the first 24 h after death. Other sequences did not enhance detection.• Left ventricular myocardial ischaemia/infarction can be demonstrated by postmortem imaging (PMI). • Ischaemia/infarction is better detected if survival time is at least 4 h. • Right ventricular ischaemia/infarction is not reliably detected by PMI. • Computed tomography angiography can demonstrate arterial occlusion.

Objectives: To examine whether the frequency of fusion-negative alveolar rhabdomyosarcoma (ARMSn) increased coincident with changes in the definition of alveolar histology. Methods: We re-reviewed alveolar rhabdomyosarcoma (ARMS) in the Children’s Oncology Group study D9803, comparing histopathology with fusion status. Results: Our review of 255 original ARMS cases (compared with a control group of 38 embryonal rhabdomyosarcomas [ERMS] cases) revealed that many had an ARMS-like densely cellular pattern with cytologic features and myogenin expression more typical of ERMS. Following re-review, 84 (33%) cases of original ARMS were rediagnosed as ERMS. All reclassified ERMS, including dense ERMS, were fusion negative, whereas 82% of confirmed ARMS cases were fusion positive. Total ARMS diagnoses returned to historic rates of 25% to 30% of all rhabdomyosarcomas, and ARMSn decreased from 37% to 18% of ARMS cases. The outcome of reclassified ERMS was similar to confirmed ERMS. Conclusions: To address the role of fusion status in risk stratification, pathologists should include both a histologic diagnosis and an evaluation of fusion status for all new ARMS diagnoses.

Background Distinguishing alveolar rhabdomyosarcoma (ARMS) from embryonal rhabdomyosarcoma (ERMS) has historically been of prognostic and therapeutic importance. However, classification has been complicated by shifting histologic criteria required for an ARMS diagnosis. Children's Oncology Group (COG) studies after IRS-IV, which included the height of this diagnostic shift, showed both an increased number of ARMS and an increase in the proportion of fusion-negative ARMS. Following diagnostic standardization and histologic re-review of ARMS cases enrolled during this era, analysis of low-risk (D9602) and intermediate-risk (D9803) rhabdomyosarcoma (RMS) studies showed that fusion status rather than histology best predicts prognosis for patients with RMS. This analysis remains to be completed for patients with high-risk RMS. Procedure We re-reviewed cases on high-risk COG studies D9802 and ARST0431 with an enrollment diagnosis of ARMS. We compared the event-free survival (EFS) and overall survival by histology, PAX-FOXO1 fusion, and clinical risk factors (Oberlin score) for patients with metastatic RMS using the log-rank test. Results Histology re-review resulted in reclassification as ERMS for 12% of D9802 cases and 5% of ARST0431 cases. Fusion-negative RMS had a superior EFS to fusion-positive RMS; however, poorer outcome for metastatic RMS was most related to clinical risk factors including age, primary site, and number of metastatic sites. Conclusions In contrast to low- or intermediate-risk RMS, in metastatic RMS, clinical risk factors have the most impact on patient outcome. PAX-FOXO1 fusion is more common in patients with a high Oberlin score, but fusion status is not an independent biomarker of prognosis.

Sudden infant death syndrome (SIDS) and sudden unexplained death in childhood (SUDC) are defined as sudden death in a child remaining unexplained despite autopsy and death scene investigation. They are distinguished from each other by age criteria, i.e. with SIDS under 1 year and SUDC over 1 year. Our separate studies of SIDS and SUDC provide evidence of shared hippocampal abnormalities, specifically focal dentate bilamination, a lesion classically associated with temporal lobe epilepsy, across the 2 groups. In this study, we characterized the clinicopathologic features in a retrospective case series of 32 children with sudden death and hippocampal formation (HF) maldevelopment. The greatest frequency of deaths was between 3 weeks and 3 years (81%, 26/32). Dentate anomalies were found across the pediatric age spectrum, supporting a common vulnerability that defies the 1-year age cutoff between SIDS and SUDC. Twelve cases (38%) had seizures, including 7 only with febrile seizures. Subicular anomalies were found in cases over 1 year of age and were associated with increased risk of febrile seizures. Sudden death associated with HF maldevelopment reflects a complex interaction of intrinsic and extrinsic factors that lead to death at different pediatric ages, and may be analogous to sudden unexplained death in epilepsy.

Background We wanted to ascertain patterns of recurrence, re-treatment, and outcome among 188 eligible patients treated for localized orbital sarcoma on IRSG Protocols III/IV, 1984–1997. Procedure Retrospective chart review. Results Twenty-four of 188 patients (12.8%) developed local (n = 22) or distant relapse (n = 2) at 0.057–7.05 years (median, 1.58) after enrollment. Ages at study entry were 0.14–17 years (median, 5 years). Initial tumor operations included biopsy (n = 20) or gross resection with microscopic residual (n = 4). Initial tumor diameters were 0.5–7 cm (median, 3). Pathologic subtypes were embryonal rhabdomyosarcoma (ERMS, n = 19), sarcoma not otherwise specified (n = 2), and alveolar RMS, botryoid ERMS, or undifferentiated sarcoma (n = 1 each). Initial treatment included vincristine/dactinomycin (n = 24) including an alkylator (n = 4) and radiotherapy (RT, n = 21). Twenty patients responded, 14 completely, 6 partially. After recurrence, patients underwent orbital exenteration (n = 10), enucleation (2), tumor excision (3), or biopsy (1); 7 had no operation, and 1 had no data. Post-relapse chemotherapy included combinations of etoposide (n = 14 patients), doxorubicin (14), ifosfamide (12), cyclophosphamide (7), and dacarbazine (n = 1). Six patients received RT, including four previously treated and two not irradiated initially. Two patients died; one at 1.79 years after contralateral brain metastasis followed by local recurrence, and another at 2.49 years after multiple local recurrences. Twenty-two patients (91.7%) survived sarcoma-free for 0.04–17 years (median, 6.9) after relapse, and 18 of 22 (82%) were alive ≥5 years after relapse. Conclusion Survival following recurrent localized orbital sarcoma appears likely after vigorous re-treatment given with curative intent. Pediatr Blood Cancer 2013; 60: 371–376. © 2012 Wiley Periodicals, Inc.

Nasal gliomas are congenital, nonmalignant rests of neuroglial tissue that typically present as a craniofacial mass. The differential diagnosis of such masses includes lesions that often require the involvement of various surgical subspecialties, including otolaryngology, neurosurgery, plastic surgery, and ophthalmology. Early surgical excision of these masses is advised to minimize nasal and craniofacial distortion. Accordingly, early diagnosis and management planning are paramount, and advances in prenatal imaging are creating a new role for obstetricians and radiologists in the initiation of diagnostic and therapeutic interventions. We describe the case history of a young patient found to have a craniofacial mass on routine prenatal ultrasound and subsequently managed with a multidisciplinary team approach.

BACKGROUND: Fine-needle aspiration (FNA) cytology is increasingly being used as a diagnostic modality for soft tissue and bone lesions. These diagnoses can be challenging because of a variety of factors, including interpretation and sampling issues. This study investigates the diagnostic utility of FNA biopsy, in addition to the diagnostic pitfalls, in soft tissue and bone cytopathology. METHODS: We retrospectively reviewed the soft tissue and bone FNAs over a 4-year period (2004-2008), along with available ancillary studies, pathological follow-up, and clinical data. The cases with a cytologic-histologic discrepancy were then reviewed. RESULTS: A total of 1114 soft tissue and bone FNAs were identified. Of the 1114 aspirates, 525 (47%) were positive for malignant cells, 505 (45.5%) were benign aspirates (including 189 benign lesions/neoplasms), 37 (3.5%) were inadequate, 34 (3%) had atypical cells, and 13 (1%) were suspicious for malignancy. Of the 586 cases (53%) with follow-up, including 445 cases with histological follow-up and 141 with ancillary studies, the overall sensitivity was 96%, the specificity was 98%, the positive predictive value was 99%, and the negative predictive value was 92%. A total of 15 false negatives and 3 false positives were identified with errors because of sampling (9 cases), interpretation (7 cases), and screening (2 cases). CONCLUSIONS: This large series demonstrates that there can be a high sensitivity and specificity in diagnosing bone and soft tissue lesions by FNA. Our data supports prior studies in the literature in showing that FNA cytology can be a valuable method for diagnosing these lesions. Cancer (Cancer Cytopathol) 2010. © 2010 American Cancer Society.

Purpose The purpose of this study was to compare the outcome of patients with intermediate-risk rhabdomyosarcoma (RMS) treated with standard VAC (vincristine, dactinomycin, and cyclophosphamide) chemotherapy to that of patients treated with VAC alternating with vincristine, topotecan, and cyclophosphamide (VAC/VTC). Patients and Methods Patients were randomly assigned to 39 weeks of VAC versus VAC/VTC; local therapy began after week 12. Patients with parameningeal RMS with intracranial extension (PME) were treated with VAC and immediate x-ray therapy. The primary study end point was failure-free survival (FFS). The study was designed with 80% power (5% two-sided α level) to detect an increase in 5-year FFS from 64% to 75% with VAC/VTC. Results A total of 617 eligible patients were entered onto the study: 264 were randomly assigned to VAC and 252 to VAC/VTC; 101 PME patients were nonrandomly treated with VAC. Treatment strata were embryonal RMS, stage 2/3, group III (33%); embryonal RMS, group IV, less than age 10 years (7%); alveolar RMS or undifferentiated sarcoma (UDS), stage 1 or group I (17%); alveolar RMS/UDS (27%); and PME (16%). At a median follow-up of 4.3 years, 4-year FFS was 73% with VAC and 68% with VAC/VTC (P = .3). There was no difference in effect of VAC versus VAC/VTC across risk groups. The frequency of second malignancies was similar between the two treatment groups. Conclusion For intermediate-risk RMS, VAC/VTC does not significantly improve FFS compared with VAC.

BACKGROUND: In the fine-needle aspiration biopsy (FNAB) diagnosis of B-cell non-Hodgkin lymphomas (B-NHL), the role of flow cytometry (FC) can be limited because of nondiagnostic findings. Fluorescence in situ hybridization (FISH) studies, similar to FC, can be helpful in establishing clonality and in subclassifying the lymphoma. The aim of the current study was to determine whether FISH studies performed on unstained direct smears improved the ability to diagnose and/or subclassify B-NHL on FNAB. METHODS: A total of 181 cases of B-NHL diagnosed by FNAB were retrieved. The cytomorphology, ancillary study results, clinical information, and available pathologic follow-up were reviewed. RESULTS: Of the 181 cases, FISH studies were performed in 106 cases (59%). The indications for FISH studies were for subclassification (59 cases; 56%) and nondiagnostic or unavailable FC results (47 cases; 44%). Of the 59 cases submitted for subclassification, 23 cases (39%) were successfully subclassified. The 47 cases with nondiagnostic or unavailable FC results included cases in which FC demonstrated a surface immunoglobulin-negative population (19 cases; 40%), had insufficient cellularity (18 cases; 38%), yielded negative results (6 cases; 13%), or had no specimen submitted (4 cases; 9%). In this group, 26 cases (55%) demonstrated an immunoglobulin heavy-chain gene rearrangement and/or chromosomal translocation. CONCLUSIONS: The results of the current study illustrate that FISH studies performed on unstained direct smears play a complementary role to FC in establishing the diagnosis and/or subclassification of B-NHL. Thus, the preparation of unstained smears at the time of FNAB can be helpful for potential FISH studies. Cancer (Cancer Cytopathol) 2009. © 2009 American Cancer Society.

Summary Objective To assess the feasibility and role of fine needle aspiration biopsy (FNAB) as a diagnostic tool in children with neck masses. Design Retrospective chart review. Setting Tertiary care children's hospital. Patients Consecutive series of 71 children with a head and neck mass who underwent FNAB as the primary diagnostic modality. Interventions FNAB was performed and interpreted by a pediatric cytopathologist. Rapid on-site analysis was performed to allow immediate assessment of specimen adequacy and to attain a preliminary diagnosis, after which routine cytologic staining was performed. Flow cytometry was performed on cytological specimens when malignancy was suspected, and open biopsy was performed when the cytologic diagnosis was in question. Main outcome measures Technical feasibility of FNAB in children, complications, cytopathological diagnoses, accuracy of rapid on-site analysis, need for subsequent diagnostic evaluations, clinical outcomes and follow-up. Results Mean age was 8.4 years (S.D. 5.3 years), with mean follow-up of 4.1 months (S.D. 9.6 months). FNAB was performed under general anesthesia in 54 cases (76%). There were no technical complications. On-site rapid interpretation was completed in 55 cases, 18/55 confirmed adequacy of specimen only, 37/55 yielded a preliminary diagnosis, and in 34/37 cases, was same as final cytopathologic result. Overall, FNAB biopsy demonstrated 64 benign lesions, 3 malignant diagnoses, 2 follicular thyroid neoplasms, and 2 non-diagnostic specimens. FNAB was the only pathological test performed in 54 (76%) cases. The most common diagnosis was reactive lymphoid hyperplasia (n = 39), followed by benign granulomatous disease (n = 8). Flow cytometry was performed on 7 specimens (non-diagnostic in 5, negative for malignancy in 2). Of the 15 cases with surgical specimens, 3 revealed a pathologic diagnosis different from initial FNAB. There were no cases in which FNAB missed a malignancy, and there were 2 cases where FNAB suggested malignancy, with benign disease subsequently found on open biopsy. Conclusions Fine needle aspiration biopsy is developing into a feasible option in diagnosing pediatric neck masses, with its main advantage being its minimally-invasive nature and avoidance of an open surgical procedure for benign persistent lymphadenitis. On-site rapid interpretation can be used successfully to confirm specimen adequacy and to give an accurate preliminary diagnosis for concerned parents. Issues to consider include the need for a specialized pediatric cytopathologist familiar with pediatric differential diagnoses, the need for general anesthesia in many cases, and the possibility of inaccurate diagnosis requiring an open procedure.

The diagnostic dilemma is discussed of a child who presented with a granulomatous process of the external ear that was originally considered granuloma annulare and was later diagnosed as epithelioid sarcoma. We present the surgical treatment and the first report of reconstruction of a lateral skull base and cheek defect with an anterolateral thigh (ALT) free flap in a pediatric patient.

Purpose Multiple drug resistance due to P-glycoprotein (P-gp) expression has been reported to be a cause of disease recurrence in osteosarcoma. Tumor specimens derived from children and young adults with osteosarcoma enrolled onto a national Intergroup trial (INT0133) were analyzed prospectively to determine the role of multiple drug resistance in osteosarcoma. Patients and Methods From October 15, 1992, to November 25, 1997, 685 patients with localized, high-grade osteosarcoma were enrolled onto INT0133. Paraffin-embedded diagnostic tumor specimens were assayed for P-gp using monoclonal antibodies C-494 (139 patients) and JSB-1 (133 patients). Percent necrosis at the time of definitive surgery (NEC), event-free survival (EFS), and overall survival (OS) were evaluated as outcome measures for patients with P-gp–positive disease and were compared with patients with P-gp–negative disease. Results P-gp expression in the biopsy specimen did not significantly increase the risk for adverse outcomes as measured by EFS, OS, or NEC. EFS for those patients with C-494–positive tumors was 59% at 4 years versus 61% at 4 years for patients with C-494–negative tumors (P = .79), or 58% at 4 years versus 61% at 4 years for patients with JSB-1–positive versus JSB-1–negative tumors (P = .65). OS for patients with C-494–positive tumors was 82% at 4 years versus 82% at 4 years for patients with C-494–negative tumors (P = .61). Conclusion Prospective analysis of the role of multiple drug resistance in localized osteosarcoma did not find that immunohistochemical analysis of P-gp expression predicted outcome for patients treated on INT0133.

The practice of central histopathologic review by expert pathologists has accompanied entry of patients onto multi-institutional therapeutic research protocols for the past half-century, and it is still a key component in the majority of therapeutic protocols conducted by the Children's Oncology Group (COG). Policies regarding pathology review have historically varied but have recently been standardized by the COG. Pretreatment central pathology review has been used to improve the accuracy of pathology data that is critical to the conduct of the study and to ensure that ineligible patients are not enrolled on a study. Pretreatment central review is unnecessary when there are established criteria for diagnosis, when institutions can uniformly apply these criteria, and when diagnoses are reliably reported. Pretreatment central review is appropriate when there are established diagnostic criteria and expert reviewers can consistently apply them but when institutional diagnoses show significant variability. It is inappropriate when there are no standard criteria or when variability exists among experts. Retrospective reviews (for example, those performed after protocol entry and treatment have occurred) historically have been used to verify institutional diagnoses and to record other features of tumors, prior to analysis of research questions. However, delayed reporting of discrepant diagnoses from retrospective reviews introduced obvious concerns regarding the appropriateness of treatment and exposed institutional pathologists and clinicians to significant professional risks. This article examines the historical usage and current status of the central pathology review process and the rationale and indications for its performance.

Morphologically, the distinction between undifferentiated embryonal sarcoma of the liver (UESL) and biliary tract rhabdomyosarcoma (RMS) can be uncertain because of some shared pathologic similarities. Patients with UESL have been consistently but erroneously enrolled in Children's Oncology Group (COG) treatment protocols because UESL was equated with RMS, despite the differing primary treatment modalities of these entities. Review of COG pathology files yielded 20 cases of UESL that were compared to 25 cases of biliary tract RMS. Clinicopathologic features including immunohistochemical staining were examined. In the UESL cases, the male:female ratio was 1:1 and the median age was 10.5 years. Histologically, hyaline globules and diffuse anaplasia were consistently present. The cases of RMS had a male:female ratio of 1.8:1 with a median age of 3.4 years and routinely lacked diffuse anaplasia and hyaline globules. Polyclonal desmin and muscle-specific actin were variably immunoreactive in UESL and RMS; however, myogenin and myogenic regulatory protein D1 (MyoD1) were uniformly negative in UESL and routinely positive in the majority of biliary tract RMS. Myogenin, in particular, was highly significant ( P = 0.0003) in distinguishing RMS from UESL. With a median follow-up of 8 months, 11 of 18 patients with UESL were still alive. The estimated 5-year survival for biliary tract RMS was 66%. Establishing the correct diagnosis of these distinct clinical and pathologic entities is important, as surgery alone may be curative in UESL, whereas initial chemotherapy is often recommended for the treatment of biliary tract RMS.