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Inflammatory myofibroblastic tumor (IMT) is a neoplasm that typically occurs in children. The genetic landscape of this tumor is incompletely understood and therapeutic options are limited. Although 50% of IMTs harbor anaplastic lymphoma kinase (ALK) rearrangements, no therapeutic targets have been identified in ALK-negative tumors. We report for the first time that IMTs harbor other actionable targets, including ROS1 and PDGFRβ fusions. We detail the case of an 8-year-old boy with treatment-refractory ALK-negative IMT. Molecular tumor profiling revealed a ROS1 fusion, and he had a dramatic response to the ROS1 inhibitor crizotinib. This case prompted assessment of a larger series of IMTs. Next-generation sequencing revealed that 85% of cases evaluated harbored kinase fusions involving ALK, ROS1, or PDGFRβ. Our study represents the most comprehensive genetic analysis of IMTs to date and also provides a rationale for routine molecular profiling of these tumors to detect therapeutically actionable kinase fusions.Significance: Our study describes the most comprehensive genomics-based evaluation of IMT to date. Because there is no “standard-of-care” therapy for IMT, the identification of actionable genomic alterations, in addition to ALK, is expected to redefine management strategies for patients with this disease. Cancer Discov; 4(8); 889–95. ©2014 AACR.See related commentary by Le and Doebele, p. 870This article is highlighted in the In This Issue feature, p. 855

PDF file - 106KB, Schematic representation of the study design. 37 IMT tumor samples from 33 patients were collected under IRB approved protocols. ALK immunohistochemistry (IHC) was performed on each of the 37 cases as standard of clinical care. Targeted next-generation sequencing (NGS) using the FoundationOne was completed in each case. 22/26 ALK IHC+ and 11/11 ALK IHC- samples were evaluable. ALK kinase fusions were detected in 20/22 (91%) of the ALK IHC+ cases. In the ALK IHC- cases, 2/11 (18%) harbored ALK fusions, 2/11 (18%) harbored PDGFRβ fusions, and 4/11 (36%) harbored ROS1 fusions. Overall, therapeutically actionable kinase fusions were detected in 28/33 (85%) of cases.

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PDF file - 59KB, Schematic representation of the index patient's treatment history. A timeline detailing the index patient's diagnosis and subsequent systemic therapies is depicted. Time in months is shown below the arrow. The timeline starts at the patient's initial diagnosis.

PDF file - 137KB, Summary of genomic coordinates for the kinase fusions identified in this study. The sample number is depicted in the far left column. For tumor samples in which a kinase fusion was identified, the genomic coordinates for of each of the fusion genes is indicated. There were no other recurrent alterations. *The FN1-ALK fusion was detected with RNA sequencing. #Sufficient material was available to verify these kinase fusions with RNA sequencing.

PDF file - 53KB, FoundationOne panel. This targeted next generation sequencing platform evaluates for 3769 exons of 236 cancer genes and 47 introns of 19 commonly rearranged genes, including 8 tyrosine kinases.

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PDF file - 87KB, Changes in the indicated laboratory parameters after 3 cycles of crizotinib. HgB: hemoglobin, Hct: hematocrit, MCV: mean corpuscular volume, ESR: erythrocyte sedimentation rate, LDH: lactate dehydrogenase.

Malignant mesothelioma is a neoplasm of serosal surfaces, most commonly affecting the pleura. The peritoneum, pericardium, and tunica vaginalis are less frequently involved. Malignant mesothelioma with EWSR1-ATF1 fusion in young adults was recently reported in the literature. Here, we present two pediatric cases of EWSR1-ATF1 translocation-associated malignant mesothelioma in the peritoneum and pericardium respectively. Both cases lacked a known exposure history. Microscopy in both cases showed predominantly epithelioid morphology with ample eosinophilic cytoplasm, and immunohistochemistry was positive for pan-keratin, calretinin, and WT1. Both cases showed EWSR1-ATF1 gene rearrangement by RNA sequencing, which was instrumental in confirming the diagnosis of malignant mesothelioma and to exclude more common pediatric sarcomas, especially in the context of limited sampling.

The classification of undifferentiated soft tissue tumors continues to evolve with the expanded application of molecular analysis in clinical practice. We report three cases of a unique soft tissue tumor in young children (5 months to 2 years old) displaying a purely fibromyxoid histology, with positive staining for desmin and CD34. In two cases, RNA sequencing detected a YWHAZ-PLAG1 gene fusion, while in the third case, a previously unreported EEF1A1-PLAG1 fusion was identified. PLAG1 fusions have been reported in several pathologic entities including pleomorphic adenoma, myoepithelial tumors of skin and soft tissue, and lipoblastoma, the latter occurring preferentially in young children. In these tumors, expression of a full length PLAG1 protein comes under the control of the constitutively active promoter of the partner gene in the fusion, and the current cases conform to that model. Overexpression of PLAG1 was confirmed by diffusely positive immunostaining for PLAG1 in all three cases. Our findings raise the possibility of a novel fibromyxoid neoplasm in childhood associated with these rare PLAG1 fusion variants. The only other report of a PLAG1-YWHAZ fusion occurred in a pediatric tumor diagnosed as a “fibroblastic lipoblastoma.” This finding raises the possibility of a relationship with our three cases, even though our cases lacked any fat component. Further studies with regard to a shared pathogenesis are required.

Background The clinical and economical value of routine submission of hernia sacs for pathological examination and scheduled clinic follow-ups after inguinal hernia and hydrocele repair has been questioned. Herein, we assessed the institutional variability in these routine practices. Methods We retrospectively reviewed patients who underwent unilateral or bilateral inguinal hernia and/or hydrocele repair, open or laparoscopically, at our institution from 2015 to 2018. Results 1181 patients were included (1074 inguinal hernias and 157 hydroceles). Of 531 specimens obtained from 446 (38%) patients, 515 (97%) were normal. 16 (3%) abnormal pathological findings included 7 with mesothelial hyperplasia, 5 with nonfunctional genital ductal remnants, 3 with ectopic adrenal cortical tissues, and 1 epidydimal structure which was not recognized at the time of surgery. 418 (35%) patients had scheduled clinic follow-ups 65 (IQR 46–94) days postoperatively. 44 (4%) patients with unexpected postoperative Emergency Department visits within 30 days of surgery were identified. Only one patient required inpatient treatment, and the rest did not require intervention or admission. The total direct cost of analyzing specimens during the study period was $30,798 CAD ($10,266/year). The average cost to detect a potentially significant finding was $1924.88/specimen and $2053.20/patient. Conclusions Routine pathological examination of hernia sacs and scheduled clinic follow-ups were associated with significant costs and predominantly nonsignificant findings. They should therefore be reserved for patients with a high clinical suspicion of injuries/abnormalities or risk factors for potential complications. Level of Evidence This is a level III evidence study.

Congenital neuroblastoma with placental involvement is exceptionally rare, but mortality is high. Detailed examination of placenta including MYCN amplification and segmental chromosomal aberrations should be performed in all suspected cases, as it is noninvasive and readily available. Maternal dissemination has not been reported. In this manuscript, we describe an infant with placental diagnosis of MYCN nonamplified congenital neuroblastoma. This is the first report of a recurrence of congenital 4S neuroblastoma following resolution in which MYCN amplification is only detected in the recurrence. Germline sequencing using a large comprehensive cancer panel did not reveal variants in candidate cancer predisposition genes.

Summary Spitzoid neoplasms typically affect young individuals and include Spitz nevus, atypical Spitz tumor, and Spitzoid melanoma. Spitz tumors can exhibit gene fusions involving the receptor tyrosine kinases NTRK1, NTRK3, ALK, ROS1, RET, or MET, or the serine-threonine kinase BRAF. Because most studies have been based on adult cases, we studied ALK fusions in Spitz nevi occurring in pediatric patients. Twenty-seven cases were screened for ALK expression by immunohistochemistry, and 6 positive cases were identified. These cases were studied further using the TruSight RNA Fusion Panel, and in 4 cases, exon 20 of the ALK gene was found to be fused to exon 14 of the MLPH (melanophilin) gene, a gene fusion that has only been reported in a Spitz nevus in an adult. The remaining 2 cases showed no fusion of ALK with any gene. The cases with the MLPH-ALK fusion showed a similar histology to that described for Spitz nevi with ALK fusions, with spindle-shaped and epithelioid melanocytes in fusiform nests with a plexiform growth pattern and infiltrative border. We created a breakapart fluorescence in situ hybridization assay for MLPH, and all 4 cases with the MLPH-ALK fusion were positive, whereas the other 23 cases in the study were negative. Thus, ALK and MLPH were fused only to each other in our series. Melanophilin is part of the melanosome trafficking apparatus together with MYO5a, TPM3, and RAB27a, all constitutively expressed in melanocytes. Kinase fusions involving MYO5A and TPM3 have been reported in Spitz tumors, and our series adds MLPH to this group.

Salivary gland tumors represent a diverse group of neoplasms that occasionally pose a diagnostic challenge for pathologists, particularly with limited sampling. Gene fusions, which may reflect genetic drivers, are increasingly recognized in a subset of these neoplasms, and can be leveraged for diagnostic purposes. We performed a retrospective analysis on a cohort of 80 benign and malignant salivary gland tumors, enriched for subtypes known to harbor recurrent fusion events, to validate the diagnostic use of a targeted RNA sequencing assay to detect fusion transcripts. Testing identified fusion genes in 71% (24/34) of pleomorphic adenoma and carcinoma-ex-pleomorphic adenoma, with 56% of cases showing rearrangement of PLAG1 and 15% HMGA2. In addition to confirming known partners for these genes, novel PLAG1 fusion partners were identified, including DSTN, NTF3, and MEG3; CNOT2 was identified as a novel fusion partner for HMGA2. In adenoid cystic carcinoma, 95% of cases (19/20) were positive for a fusion event. MYB was rearranged in 60% (12/20), MYBL1 in 30% (6/20), and NFIB in 5% (1/20); two tumors exhibited novel fusion products, including NFIB-TBPL1 and MYBL1-VCPIP1. Fusion genes were identified in 64% (9/14) of cases of mucoepidermoid carcinoma; MAML2 was confirmed to partner with either CRTC1 (43%) or CRTC3 (21%). One salivary duct carcinoma was found to harbor a novel RAPGEF6-ACSL6 fusion gene. Finally, as anticipated, gene fusions were not detected in any of the five acinic cell carcinomas included in the cohort. In summary, targeted RNA sequencing represents a diagnostically useful ancillary technique for identifying a variety of existing, and novel, fusion transcripts in the classification of salivary gland neoplasms.

Published histologic studies of the hilar plate or entire biliary remnant at the time of Kasai portoenterostomy (KHPE) have not provided deep insight into the pathogenesis of biliary atresia, relation to age at surgery, prognosis or the basis for successful drainage. We report detailed histologic findings in 172 centrally reviewed biliary remnants with an average of 6 sections per subject. Active lesions were classified as either necroinflammatory (rare/clustered in a few subjects) or active concentric fibroplasia with or without inflammation (common). Inactive lesions showed bland replacement by collagen and fibrous cords with little or no inflammation. Heterogeneity was common within a given remnant; however, relatively homogenous histologic patterns, defined as 3 or more inactive or active levels in the hepatic ducts levels, characterized most remnants. Homogeneity did not correlate with age at KHPE, presence/absence of congenital anomalies at laparotomy indicative of heterotaxy and outcome. Remnants from youngest subjects were more likely than older subjects to be homogenously inactive suggesting significantly earlier onset in the youngest subset. Conversely remnants from the oldest subjects were often homogenously active suggesting later onset or slower progression. More data are needed in remnants from subjects

A 3-year-old boy with high-risk precursor-B ALL presented with abdominal pain, vomiting, and hypoalbuminemia just before his second scheduled course of high-dose methotrexate in interim maintenance. Examination was significant for epigastric tenderness and periorbital edema. Abdominal imaging revealed a circumferential thickening of the stomach with an increased mucosal enhancement and a mild circumferential thickening of segments of small bowel loops. Cytomegalovirus (CMV) of the patient, determined by PCR, in blood was positive with a low titer and was subsequently negative. Upper endoscopy revealed hypertrophic rugae and folds in the stomach and duodenum, and biopsy showed giant gastric folds and foveolar hyperplasia but was negative for CMV. He received supportive care and a 2-week course of ganciclovir and Cytogam with clinical improvement. We report a case of Menetrier's disease (Protein-losing gastropathy), which was diagnosed in a child with acute leukemia. Menetrier's disease should be considered in any patient with symptoms referable to the gastrointestinal tract and thickened stomach and bowel loops detected by radiologic imaging., Highlights • Menetrier's disease (protein-losing gastropathy) is a rare disease in children, with only reported 50–60 cases. • Menterier's disease has been reported in few oncology adult patients as a paraneoplastic phenomenon or with BMT. • Our patient may be the first case of Menetrier's disease to be reported in a child with acute leukemia. • The diagnosis was difficult and required multi-modality imaging, upper GI endoscopy and the examination of gastric biopsy.

Until recently, undifferentiated round cell sarcomas (URCS) in infants have been considered a wastebasket diagnosis, composed of various pathologic entities and lacking consistent genetic alterations. The recent identification of recurrent BCOR internal tandem duplications (ITD) and less common alternative YWHAE-NUTM2B/E fusions in half of infantile URCS and the majority of so-called primitive myxoid mesenchymal tumors of infancy (PMMTI) suggests a common pathogenesis with clear cell sarcoma of the kidney which also harbors the same genetic alterations. These tumors also share a similar morphology and immunoprofile, including positivity for BCOR, cyclin D1, and SATB2. In this study, we investigate the largest cohort to date of genetically confirmed URCS and PMMTI with BCOR ITD or YWHAE fusions to better define their morphologic spectrum and clinical behavior. Twenty-eight cases harbored BCOR ITD and five YWHAE fusions, occurring in 29 infants and 4 children, 19 males and 14 females. Microscopically, 20 were classified as URCS and 13 as PMMTI. Follow-up was available in 25 patients, with 14 (56%) succumbing to their diseases at a mean duration of 18-months follow-up (range: 2-62). Six patients remained with no evidence of disease at a mean follow-up of 63 months (range: 4-192), four patients were still alive with disease (mean follow-up: 46 months, range: 4-120), and one died of other causes. Local recurrence and distant metastasis were each observed in 11/25 (44%) of the patients. The overall survival was 42% at 3 years and 34% at 5 years (median survival: 26 months). There was no statistically significant survival difference between cases diagnosed as URCS and PMMTI and between those with BCOR ITD and YWHAE fusions.

Whereas neuroblastoma is the most common extracranial solid tumor of childhood, less than 5% of cases occur in adults. Pediatric neuroblastoma shows marked heterogeneity of histology and molecular biology. Information about this tumor in adults is limited, especially regarding molecular biology. We report a series of nine neuroblastoma cases diagnosed in adulthood (18 to 40 years old) with molecular biologic characterization in seven. All tumors were Schwannian stroma-poor, and mostly poorly differentiated. Tumors expressed neural markers including PHOX2B, NB84, synaptophysin, chromogranin, CD56, neuron-specific enolase, and PGP9.5. Two out of six cases expressed ALK and one had the F1174 L mutation reported in childhood neuroblastoma. Fluorescent in situ hybridization (FISH) revealed MYCN amplification in 2/7 cases, chromosome 1p deletion in 1/5 cases and 17q gain in 4/4 cases. One in five cases showed loss of ATRX expression by immunohistochemistry and alternate lengthening of telomeres by FISH. Zero out of five cases showed rearrangement of the TERT gene by FISH, but one case showed high level amplification. In conclusion, the morphology and immunophenotype of adult-onset neuroblastoma are similar to pediatric cases although less differentiated than some childhood tumors. Similarly, molecular genetic alterations in adult-onset neuroblastoma are not unique to this age group. However, 80% of cases tested showed genetic changes that would promote maintenance of telomeres, which is a molecular marker of high risk cases. This may help explain the poor response in adults to pediatric treatment protocols. Additional studies to characterize the biology of this tumor in the adult age group will facilitate the design of more personalized therapeutic approaches.

Alveolar soft part sarcoma (ASPS) is a rare malignancy that, since its initial description, remains a neoplasm of uncertain histogenesis. The disease-defining molecular event characterizing the diagnosis of ASPS is the ASPSCR1-TFE3 fusion gene. Following identification of an index case of ASPS with a novel TFE3 fusion partner, we performed a retrospective review to determine whether this represents an isolated event. We identified two additional cases, for a total of three cases lacking ASPSCR1 partners. The average patient age was 46 years (range, 17-65); two patients were female. The sites of origin included the transverse colon, foot, and dura. Each case exhibited a histomorphology typical of ASPS, and immunohistochemistry was positive for TFE3 in all cases. Routine molecular testing of the index patient demonstrated a HNRNPH3-TFE3 gene fusion; the remaining cases were found to have DVL2-TFE3 or PRCC-TFE3 fusion products. The latter two fusions have previously been identified in renal cell carcinoma; to our knowledge, this is the first report of a HNRNPH3-TFE3 gene fusion. These findings highlight a heretofore underrecognized genetic diversity in ASPS, which appears to more broadly molecularly overlap with that of translocation-associated renal cell carcinoma and PEComa. These results have immediate implications in the diagnosis of ASPS since assays reliant upon ASPSCR1 may yield a false negative result. While these findings further understanding of the molecular pathogenesis of ASPS, issues related to the histogenesis of this unusual neoplasm remain unresolved.

The family of pediatric fibroblastic and myofibroblastic proliferations encompasses a wide spectrum of pathologic entities with overlapping morphologies and ill-defined genetic abnormalities. Among the superficial lesions, lipofibromatosis (LPF), composed of an admixture of adipose tissue and fibroblastic elements, in the past has been variously classified as infantile fibromatosis or fibrous hamartoma of infancy. In this regard, we have encountered a group of superficial soft tissue tumors occurring in children and young adults, with a notably infiltrative growth pattern reminiscent of LPF, variable cytologic atypia, and a distinct immunoprofile of S100 protein and CD34 reactivity, suggestive of neural differentiation. SOX10 and melanocytic markers were negative in all cases tested. In contrast, a control group of classic LPF displayed bland, monomorphic histology and lacked S100 protein immunoreactivity. To define the pathogenetic abnormalities in these seemingly distinctive groups, we performed RNA sequencing for fusion gene discovery in 2 cases each, followed by screening for any novel alterations identified in a larger cohort representing both entities. The 2 index LPF-like neural tumors (LPF-NT) showed TPR-NTRK1 and TPM3-NTRK1 gene fusions, which were further validated by fluorescence in situ hybridization (FISH) and reverse transcription polymerase chain reaction. Subsequent FISH screening of 14 LPF-NT identified recurrent NTRK1 gene rearrangements in 10 (71%) cases. Of the NTRK1-negative LPF-NT cases, 1 case each showed ROS1 and ALK gene rearrangements. In contrast, none of the 25 classic LPFs showed NTRK1 gene rearrangements, although regional abnormalities were noted in the 1q21-22 region by FISH in a majority of cases. Furthermore, NTRK1 immunostaining was positive only in NTRK1-rearranged S100-positive LPF-NT but negative in classic LPF. These results suggest that NTRK1 oncogenic activation through gene fusion defines a novel and distinct subset of soft tissue tumors resembling LPF, but displaying cytologic atypia and a neural immunophenotype, provisionally named LPF-like neural tumors.

BACKGROUND Thyroid malignancy is rare in young children, although the incidence increases sharply during adolescence. Nodular thyroid disease and thyroid cancer in children differ substantially from those in adults, because the rates of malignancy among children are roughly 5-fold higher, and local and distant metastases as well as recurrences are more common. Even with the recent introduction of pediatric guidelines, there remains a paucity of pediatric data on which to base clinical decision making. The objectives of this study were to characterize the outcomes of fine-needle aspiration biopsy (FNAB) of nodular thyroid disease at a pediatric tertiary-care institution over a 24-year period and to relate cytopathology to histopathology and management decisions in this population. METHODS A retrospective review of patients who underwent preoperative FNAB and thyroid surgery between 1992 and 2015 was conducted. In total, 207 nodules were biopsied among 178 patients. RESULTS Adequate FNAB samples were obtained in 74% of biopsies. Sixty-five patients underwent thyroidectomy after FNAB. In this group, the malignancy rates for lesions deemed benign, atypical, suspicious, and malignant on FNAB cytology were 16%, 67%, 71%, and 100%, respectively. Twenty-seven individuals underwent >1 biopsy; however, no malignancies were identified in these patients. Surprisingly, the rate of malignancy in patients who underwent preoperative FNAB was not significantly different from the rate in those who proceeded directly to surgery (n = 146). CONCLUSIONS FNAB remains a valuable tool for preoperative assessment of pediatric thyroid nodules. When samples are adequate for assessment, cytology other than clearly “benign” merits referral for diagnostic or therapeutic thyroidectomy. In this series, FNAB did not reduce rates of surgery for benign disease. Cancer Cytopathol 2016. © 2016 American Cancer Society.

Anhidrotic Ectodermal Dysplasia with Immunodeficiency (EDA-ID) is a pleotropic disorder characterized by dental abnormalities, eccrine sweat dysgenesis, specific facies, fine sparse hair, pale wrinkled skin, and variable immune defects. The condition is caused by hypomorphic mutations (NF) κB Essential modifier protein (NEMO) gene. The clinical phenotype between patients is heterogenous and variable.Here we report a patient with a known NEMO mutation presenting with clinical features consistent with EDA-ID, except for paradoxical hyperhidrosis despite having a biopsy-proven reduced number of sweat glands.Statement of novelty: We report a patient with X-linked EDA-ID due to NEMO deficiency who presented with marked diaphoresis despite biopsy-proven reduced sweat glands and ectodermal dysplasia.

© 2018 American Medical Association. All rights reserved. IMPORTANCE Understanding the role of chorioamnionitis, a major factor leading to preterm birth, in the pathogenesis of neonatal brain injury and adverse neurodevelopmental outcomesmay help in identifying potentially modifiable perinatal variables affecting brain health and outcomes among children born preterm. OBJECTIVE To evaluate whether histologic chorioamnionitis among neonates born very preterm is associated with intraventricular hemorrhage (IVH) and punctate white matter injury (WMI) or with adverse neurodevelopmental outcomes during early childhood. DESIGN, SETTING, AND PARTICIPANTS Prospective cohort study conducted across 3 academic centers (from April 2006 to September 2013 in Canada, from March 2007 to March 2013 in the Netherlands, and from January 2004 to August 2011 in the United States). Children who were born preterm (24-32 weeks' gestation) and who had undergone a placental pathologic evaluation, magnetic resonance imaging as soon as clinically stable, and Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III) assessments between 18 and 24 months' corrected age (CA) were included. Magnetic resonance imaging scans were assessed for grade of IVH and volume of punctate WMI. Data analysis occurred between December 2016 and January 2018. Final multivariable analyses examining the association of chorioamnionitis with motor and cognitive outcomes accounted for academic center and perinatal and postnatal factors. MAIN OUTCOMES AND MEASURES Punctate WMI volume and IVH detected on neonatal magnetic resonance imaging scans; motor and cognitive outcomes defined using Bayley-III assessments conducted among these children between 18 and 24 months' CA. RESULTS Of 350 neonates (182 male) in the final cohort, 145 (41.4%) had histologic chorioamnionitis. Gestational age was significantly lower among those with chorioamnionitis (median, 26.4 weeks; interquartile range [IQR], 25.6-27.7 weeks) than among those without chorioamnionitis (median, 28.0 weeks; IQR, 27.0-29.7 weeks). Chorioamnionitis was not associated with IVH or WMI, nor was it associated with worse motor outcomes in univariable or multivariable analyses (adjusted Bayley-III motor score, -2.2; 95%CI, -5.6 to 1.3). Cognitive scores were marginally yet statistically significantly lower among children with chorioamnionitis (median, 105; IQR, 95-110) than among those without chorioamnionitis (median, 105; IQR, 100-115) in the univariable model. This difference was attenuated in the multivariable model (adjusted Bayley-III cognitive score, -3.0; 95%CI, -6.4 to 0.4). CONCLUSIONS AND RELEVANCE Histologic chorioamnionitis was not associated with IVH or WMI near birth or with worse cognitive or motor outcomes from 18 to 24 months' CA after accounting for perinatal factors. Postnatal factors attenuated the association between chorioamnionitis and neurodevelopmental outcomes, highlighting the importance of preventing postnatal illness, such as infection, to promote optimal outcomes among children born preterm.

Hepatoblastoma is the most common hepatic malignancy of childhood with known genetic predispositions and perinatal risk factors, with rare case reports occurring in the setting of cirrhosis. This case describes a young patient with cirrhosis attributed to early-onset hereditary hemochromatosis who was diagnosed with hepatoblastoma with uncommon histologic findings, evidence of chemotherapy resistance who ultimately succumbed to her disease. It is important to consider diagnoses beyond hepatocellular carcinoma in this scenario and consider early biopsy. With atypical histology, the tumor may respond poorly to conventional treatment and aggressive surgery or intensive therapy should be contemplated.

We hypothesized that if infection is the proximate cause of congenital biliary atresia, an appropriate response to antigen would occur in lymph nodes contiguous with the biliary remnant. We compared the number of follicular germinal centers (GC) in 79 surgically excised hilar lymph nodes (LN) and 27 incidentally discovered cystic duct lymph nodes (CDLN) in 84 subjects at the time of hepatic portoenterostomy (HPE) for biliary atresia (BA) to autopsy controls from the pancreaticobiliary region of non-septic infants > 3 months old at death. All 27 control LN lacked GC a sign in infants of a primary response to antigenic stimulation. GC were found in 53% of 106 LN in 56 of 84 subjects. Presence of GC and number of GC/LN was unrelated to age at onset of jaundice but was related to older age at HPE. Absent GC in visible and incidentally removed CDLN predicted survival with the native liver at 2 and 3 years after HPE, p=0.03, but significance was lost at longer intervals. Visible surgically excised LN contiguous with the most proximal biliary remnants had one or more well-formed reactive GC in only 26/51 subjects. No correlation existed between GC in hilar LN and frank inflammatory activity in the proximal hepatic duct, or between the latter and outcome after HPE. GC in hilar LN correlated with generalized neutrophilic pericholangitis in 80 contemporaneous liver biopsies (p=0.04) but not with overall intensity of portal cellular infiltrates. The absence of consistent evidence of antigenic stimulation in LN contiguous with the biliary remnant argues for a limited role for infection in the etiology of biliary atresia. The intense inflammatory lesions occasionally found in remnants and the acute pericholangitis found in a minority of liver biopsies could be secondary either to bile-induced injury or secondary infection established as obstruction evolves.

The contemporary oncologic pathology report conveys diagnostic, prognostic, predictive, and hereditary predisposition information. Each component may be premised on a morphologic feature or a biomarker. Clinical validity and reproducibility are paramount as is standardization of reporting and clinical response to ensure individualization of patient care. Regarding hereditary predisposition, morphology-based genetic referral systems in some instances have eclipsed genealogy-based systems, for example, cell type in ovarian cancer and BRCA screening. In other instances such as Lynch syndrome, morphology-based schemas supplement clinical schemas and there is an emerging standard of care for reflex biomarker testing. Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) syndrome predisposes patients to uterine and cutaneous leiomyomas (LMs) and renal cell carcinomas (RCCs). Several authors have emphasized the role pathologists may play in identifying this syndrome by recognizing the morphologic characteristics of syndromic uterine LMs and RCCs. Recently immunohistochemical overexpression of S-(2-succinyl) cysteine (2SC) has been demonstrated as a robust biomarker of mutation status in tumors from HLRCC patients. In this blinded control-cohort study we demonstrate that the proposed morphologic criteria used to identify uterine LMs in HLRCC syndrome are largely irreproducible among pathologists and lack sufficient robustness to serve as a trigger to triage cases for 2SC immunohistochemistry or patients for further family/personal history inquiry. Although refinement of morphologic criteria can be considered, in view of the availability of a clinically robust biomarker, consideration should be given to reflex testing of uterine LMs with an appropriate age cut off or in the setting of a suspicious family history.

The liver biopsy guides diagnostic investigation and therapy in infants with undiagnosed cholestasis. Histologic features in the liver may also have prognostic value in the patient with biliary atresia (BA). We assessed the relative value of histologic features in 227 liver needle biopsies in discriminating between BA and other cholestatic disorders in infants enrolled in a prospective Childhood Liver Disease Research Network (ChiLDReN) cohort study by correlating histology with clinical findings in infants with and without BA. In addition, we reviewed 316 liver biopsies from clinically proven BA cases and correlated histologic features with total serum bilirubin 6 months after hepatoportoenterostomy (the Kasai procedure, HPE) and transplant-free survival up to 6 years. Review pathologists were blinded to clinical information except age. Semiquantitative scoring of 26 discrete histologic features was based on consensus. Bile plugs in portal bile ducts/ductules, moderate to marked ductular reaction, and portal stromal edema had the largest odds ratio for predicting BA versus non-BA by logistic regression analysis. The diagnostic accuracy of the needle biopsy was estimated to be 90.1% (95% confidence interval [CI]: 85.2%, 94.9%), whereas sensitivity and specificity for a diagnosis of BA are 88.4% (95% CI: 81.4, 93.5) and 92.7% (95% CI: 84.8, 97.3), respectively. No histologic features were associated with an elevated serum bilirubin 6 months after HPE, although it (an elevated serum bilirubin) was associated with an older age at HPE. Higher stages of fibrosis, a ductal plate configuration, moderate to marked bile duct injury, an older age at HPE, and an elevated international normalized ratio were independently associated with a higher risk of transplantation.

Thyroid malignancy is rare in young children, although the incidence increases sharply during adolescence. Nodular thyroid disease and thyroid cancer in children differ substantially from those in adults, because the rates of malignancy among children are roughly 5-fold higher, and local and distant metastases as well as recurrences are more common. Even with the recent introduction of pediatric guidelines, there remains a paucity of pediatric data on which to base clinical decision making. The objectives of this study were to characterize the outcomes of fine-needle aspiration biopsy (FNAB) of nodular thyroid disease at a pediatric tertiary-care institution over a 24-year period and to relate cytopathology to histopathology and management decisions in this population.A retrospective review of patients who underwent preoperative FNAB and thyroid surgery between 1992 and 2015 was conducted. In total, 207 nodules were biopsied among 178 patients.Adequate FNAB samples were obtained in 74% of biopsies. Sixty-five patients underwent thyroidectomy after FNAB. In this group, the malignancy rates for lesions deemed benign, atypical, suspicious, and malignant on FNAB cytology were 16%, 67%, 71%, and 100%, respectively. Twenty-seven individuals underwent1 biopsy; however, no malignancies were identified in these patients. Surprisingly, the rate of malignancy in patients who underwent preoperative FNAB was not significantly different from the rate in those who proceeded directly to surgery (n = 146).FNAB remains a valuable tool for preoperative assessment of pediatric thyroid nodules. When samples are adequate for assessment, cytology other than clearly "benign" merits referral for diagnostic or therapeutic thyroidectomy. In this series, FNAB did not reduce rates of surgery for benign disease. Cancer Cytopathol 2016;124:801-10. © 2016 American Cancer Society.

Soft tissue undifferentiated round cell sarcoma (URCS) occurring in infants is a heterogenous group of tumors, often lacking known genetic abnormalities. On the basis of a t(10;17;14) karyotype in a pelvic URCS of a 4-month-old boy showing similar breakpoints with clear cell sarcoma of kidney (CCSK), we have investigated the possibility of shared genetic abnormalities in CCSK and soft tissue URCS. Most CCSKs are characterized by BCOR exon 16 internal tandem duplications (ITDs), whereas a smaller subset shows YWHAE-NUTM2B/E fusions. Because of overlapping clinicopathologic features, we have also investigated these genetic alterations in the so-called primitive myxoid mesenchymal tumor of infancy (PMMTI). Among the 22 infantile URCSs and 7 PMMTIs selected, RNA sequencing was performed in 5 and 2 cases, with frozen tissue, respectively. The remaining cases with archival material were tested for YWHAE-NUTM2B/E by fluorescence in situ hybridization (FISH) or reverse transcription-polymerase chain reaction (RT-PCR), and BCOR ITD by PCR. A control group of 4 CCSKs and 14 URCSs in older children or adults without known gene fusion and 20 other sarcomas with similar histomorphology or age at presentation were also tested. A YWHAE-NUTM2B fusion was confirmed in the index case by FISH and RT-PCR, whereas BCOR ITD was lacking. An identical YWHAE-NUTM2B fusion was found in another URCS case of a 5-month-old girl with a back lesion. The remaining cases and control group lacked YWHAE gene rearrangements; instead, consistent BCOR ITDs, similar to CCSK, were found in 15/29 (52%) infantile sarcoma cases (9/22 infantile URCS and 6/7 PMMTI). In the control cohort, BCOR ITD was found only in 3 CCSK cases but not in the other sarcomas. Histologically, URCS with both genotypes and PMMTI shared significant histologic overlap, with uniform small blue round cells with fine chromatin and indistinct nucleoli. A prominent capillary network similar to CCSK, rosette structures, and varying degree of myxoid change were occasionally seen. BCOR ITD-positive tumors occurred preferentially in the somatic soft tissue of the trunk, abdomen, and head and neck, sparing the extremities. RNAseq showed high BCOR mRNA levels in BCOR ITD-positive cases, compared with other URCSs. In summary, we report recurrent BCOR exon 16 ITD and YWHAE-NUTM2B fusions in half of infantile soft tissue URCS and most PMMTI cases, but not in other pediatric sarcomas. These findings suggest a significant overlap between infantile URCS and CCSK, such as age at presentation, histologic features, and genetic signature, thus raising the possibility of a soft tissue counterpart to CCSK.

Neonates with cholestasis may undergo many tests before biliary atresia (BA) or an alternative diagnosis is reached, and delayed intervention may worsen outcomes. An optimal diagnostic approach to reduce risk, cost, and delay has yet to be defined. The purpose of this study was to develop an algorithm that rapidly and accurately excludes BA for infants with cholestatic jaundice.A single-center retrospective comparison of diagnostic workup was made between cholestatic infants with BA, and those without BA who underwent hepatobiliary iminodiacetic acid (HIDA) scan during admission. Patients were born between 2000 and 2010 and those older than 100days at assessment were excluded. Sensitivity and specificity analysis of predictive variables was performed and an algorithm constructed.There were 45 BA and 167 non-BA patients. Some variables were 100% sensitive for the exclusion of BA: conjugated bilirubin2.5mg/dL, gamma-glutamyl transpeptidase150U/L, excretion on HIDA, or a normal percutaneous cholangiogram. Clinical variables and ultrasound were less useful as screening tests owing to low specificity and sensitivity, respectively. Liver biopsy was 98% sensitive and 84% specific in the diagnosis of BA. An algorithm was constructed that rules out BA with a negative laparotomy rate of 3-22%.We propose a screening algorithm for infants with conjugated hyperbilirubinemia that permits efficient exclusion of BA with minimal invasive testing and with a low risk of negative laparotomy. This algorithm now requires prospective evaluation to determine its diagnostic accuracy and its ability to reduce hospital costs, patient morbidity, and time to Kasai portoenterostomy in patients with BA.

Background Tumour-associated macrophages (TAM) are associated with treatment failure in adults with Hodgkin lymphoma (HL). Equivalent data in paediatric HL are sparse. We aimed to determine the prognostic significance of TAM and Reed-Sternberg (RS) cells in paediatric HL. Methods All children aged 0–18 with HL between 1980 and 2009 with available diagnostic biopsy material were identified. A treatment failure-enriched cohort was assembled. Demographic, disease and outcome data were abstracted. Tissue microarrays with duplicate cores were constructed from diagnostic biopsy material and stained with immunohistochemical markers for TAM (CD68, CD163) and RS (CD30). A high score was defined as >5% positive cells relative to overall cellularity in any core. The association of candidate variables with event-free survival (EFS) was determined using Cox proportional hazards. Results The final study cohort comprised 96 patients with a median age of 14 years (interquartile range 11–15). Agreement on scores between cores from the same biopsy revealed weighted kappas of 0.60, 0.68 and 0.73 for CD30, CD68 and CD163 respectively, indicating moderate tumour heterogeneity. In univariate analysis, a high CD30 score was significantly associated with treatment failure (hazard ratio (HR) 2.27; 95th confidence interval 1.01–5.11; p Conclusions Unlike adult HL, a higher percentage of RS cells was associated with poor outcome, while a higher percentage of TAM was not. Adult HL findings may not extend to paediatric HL. Cooperative group trials of paediatric HL should prospectively determine the association of different components of the tumour microenvironment with outcome.

To define the pathological features associated with response to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in NSCLC, we have evaluated tumor histopathological features and immunohistochemical markers of proliferation (Ki-67) and epithelial mesenchymal transition (EMT) in 36 resected early stage NSCLC from patients treated preoperatively with gefitinib for 28 days. Tumors studied included 7 squamous cell carcinoma, 27 adenocarcinoma (ADC), one adenosquamous carcinoma, and one large cell carcinoma. Six of the ADC harboured an EGFR tyrosine kinase domain (TKD) mutation; five were the sensitizing type. Five ADC with TKD mutation demonstrated non-mucinous lepidic growth pattern as the dominant histological feature. Post-gefitinib treated EGFR TKD mutant tumors demonstrated lower tumor cellularity and proliferative index compared to wild type ADC and non-ADC cases, features correlating with clinical response. Responding tumors also showed large areas of fibrosis, within which focal residual viable tumor cells were noted. However, there was no significant correlation between the degree of fibrosis and radiological changes in tumor size. Expression of EMT markers was not associated with significant change in tumor size. The results suggest that radiologically assessed response to EGFR TKI in NSCLC is related to loss of tumor cellularity and reduced tumor cell proliferation, but residual viable tumor cells may persist even after prolonged treatment. Neoadjuvant studies in early stage NSCLC offer a unique opportunity to evaluate pathological and biomarker changes induced by targeted drugs.

Erdheim-Chester disease is a rare xanthomatosis that may present with characteristic radiologic and histologic features. There have been conflicting reports regarding the nature of this process, including whether it represents a reactive or neoplastic lesion. We present the clinical histories, pathologic findings, and an analysis of clonality using the HUMARA assay in two patients diagnosed with Erdheim-Chester disease. One case has previously been documented in the literature. Histologically, both cases demonstrated sheets of foamy xanthomatous histiocytes with widespread infiltration of the viscera. These regions were punctuated by variable amounts of inflammation, including lymphocytes, plasma cells, and occasional Touton-type giant cells. The histiocytes were immunoreactive for CD68 and CD163; they did not stain with S100 or CD1a. One case was found to be monoclonal; however, the second case had extensive DNA degradation; thus, clonality could not be assessed. In addition to contributing an additional report of this rare disease to the literature, we demonstrate the histiocytes to express CD163, thereby further supporting a monocyte/macrophage basis. Moreover, in confirming clonality, our observations lend additional evidence to the view that Erdheim-Chester disease represents a neoplastic process.

Oncogenic kinase fusions are validated targets for cancer therapy. With the advent of next generation sequencing (NGS) based clinical diagnostic tools, the detection of these kinase fusions is rapidly increasing across multiple adult and pediatric tumor types. However, there remains a need to better understand the functional impact of these fusions in order to help direct clinical therapies. To study fusion biology, we have made use of a large collection of inflammatory myofibroblastic tumor (IMT) samples. IMT is a rare mesenchymal malignancy, which typically occurs in children. We have recently demonstrated that IMTs harbor multiple therapeutically actionable kinase fusions, including ALK, ROS1, and PDGFRB fusions, using a targeted capture-based NGS assay in a CLIA laboratory (Foundation Medicine). Our initial results demonstrated both previously described ALK fusions, including TPM3-, TPM4-, TFG-, and RANBP2-ALK as well as novel ALK fusions, including PRKAR1A-ALK and LMNA-ALK. Although the presence of ALK fusions within a tumor has been correlated with response to ALK inhibitor therapy, the role that the 5′ prime partner gene may play in the functional biology of the fusion has not been systematically investigated. To address this, we stably transfected cDNAs encoding LMNA-ALK, RANBP2-ALK, FN1-ALK, TFG-ALK, and PRKAR1A-ALK into BA/F3 cells. All X-ALK (X = the fusion partner) variants were tyrosine phosphorylated and their subcellular distribution was in agreement with that observed in the primary tumors harboring the identical fusion. Subcellular localization was altered as a function of the fusion partner. For example, LMNA-ALK was predominantly cytoplasmic while RANBP2-ALK was predominantly perinuclear. Additionally, we compared proliferation rates, downstream signaling, and sensitivity to various structurally different ALK inhibitors amongst all of the X-ALK fusions. Overall, our results suggest that the specific fusion partner may affect the properties of the ALK fusion protein, including sensitivity to ALK inhibitors currently in clinical use. To date, most ALK fusions are detected by immunohistochemistry for ALK overexpression or by “break-apart” fluorescence in situ hybridization (FISH), techniques which may be falsely negative in some settings and in others cannot discern specific fusion present. As the role of NGS increases in clinical diagnostics, our findings may provide further biological and clinical insights into these kinase fusions. Citation Format: Merrida A. Childress, Abha Gupta, Doron Lipson, Geoff Otto, Tina Brennan, Catherine T. Chung, Scott C. Borinstein, Jeffrey S. Ross, Phillip J. Stephens, Vincent A. Miller, Cheryl M. Coffin, Jason L. Hornick, Christine M. Lovly. Understanding oncogenic fusions: Lessons learned from inflammatory myofibroblastic tumor. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 497. doi:10.1158/1538-7445.AM2015-497

PURPOSE: To evaluate the role of apparent diffusion coefficient (ADC) values in distinguishing DCIS grades and identifying the presence of micro-invasive/invasive disease. METHODS AND MATERIALS: REB approved study with informed consent obtained from 70 women (age 36-84) scheduled for core-biopsy with results of 71 non-invasive/high-risk breast lesions. All patients underwent surgery and were assessed pre-operatively using diffusion weighted (DWI)-MRI. Lesion size, morphology and ADC values were recorded. The Kruskal Wallis or one-way ANOVA test and Pearson correlation coefficient were used to study the association between ADC values and the analyzed MRI lesion characteristics. Logistic regression analysis was used to evaluate the ability of ADC values to predict the presence of invasion. RESULTS: Of 71 cases, 45.1% were imaged on a 3T magnet and 54.9% on 1.5 T. Final pathology demonstrated invasive cancer in 26.8%, micro-invasion in 18.3% and pure DCIS in 59.2%. On 3T, mean ADC value was 1.20 ×10-3 mm2/s ± 0.48 (SD) (range, 0.47 - 1.78 ×10-3 mm2/s) for non-high grade DCIS, 1.23 × 10-3 mm2/s ± 0.40 (SD) (range, 0.26 - 1.77 ×10-3 mm2/s) for high-grade DCIS, and 1.15 × 10-3 mm2/s ± 0.45 (SD) (range, 0.26 - 1.75 ×10-3 mm2/s) for invasive/microinvasive disease. On 1.5T, mean ADC value was 1.04 × 10-3 mm2/s ± 0.41 (SD) (range, 0.15 - 1.85 ×10-3 mm2/s) for non-high grade DCIS, 1.01 × 10-3 mm2/s ± 0.37 (SD) (range, 0.06 - 1.76 ×10-3 mm2/s) for high-grade DCIS, and 1.11 × 10-3 mm2/s ± 0.30 (SD) (range, 0.64 - 1.76 ×10-3 mm2/s) for invasive/microinvasive disease. Based on logistic regression analysis, mean ADC value was not a significant predictor for invasiveness using 1.5 T [OR = 2.6 (95% CI (0.409, 17.12)), p = 0.3] or 3T [OR = 0.4 (95% CI (0.076, 2.399)), p = 0.3] CONCLUSION: Mean ADC acquired using a 1.5T or 3T MRI was unable to predict high-grade or invasive disease in biopsy-proven DCIS lesions. Further work is exploring voxel-based approaches that may better appreciate tumor heterogeneity and identify sub-regions of tumor with these higher risk features. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-02-10.

Patients with cystic fibrosis (CF) have abnormal concentrations and composition of electrolytes and macromolecules in gastrointestinal secretions. Such alterations could change intestinal surface properties, such as surface hydrophobicity, and may influence the adhesion of macromolecules, bacteria, or microbial toxins to the intestinal surface. The objective of this study was to compare the surface hydrophobicity of the gastrointestinal tract in wild type and CF mice. We used axisymmetric drop shape analysis-contact diameter to determine surface hydrophobicity by measuring contact angles of sessile water droplets placed onto epithelial surfaces. In wild type mice, there were no differences in contact angles between the duodenum, upper jejunum, lower jejunum, and ileum. The contact angle of the gastric mucosa was lower than the rest of the gastrointestinal tract. Contact angles of the proximal colon and distal colon were both higher than that of the gastric mucosa and those of the small intestinal sections. In CF mice, contact angles along the gastrointestinal tract followed the same pattern as in wild type mice. However, contact angles in the ileum and proximal colon of CF mice were greater than those from wild type mice. This study of the murine intestine showed regional differences in surface hydrophobicity comparable to those observed in other mammalian species. In addition, we showed that the ileum and proximal colon of CF mice were more hydrophobic than the corresponding segments in wild type mice. These observations are of potential clinical relevance because patients with CF exhibit clinical manifestations of gastrointestinal disease primarily in the ileum and proximal colon.