Establishing normal ranges for fetal and neonatal small and large intestinal lengths: results from a prospective postmortem study.

Objective: To establish reference intervals (RIs) for fetal and neonatal small and large intestinal lengths. Methods: Linear measurements on small and large intestines were made upon postmortem examination of 131 preterm and term infants with gestational ages between 13 and 41 weeks. All cases were referred from the Eastern Ontario and Western Québec regions to a tertiary care hospital. Age and sex partitions were considered and RI limits were estimated. Results: Data consisted of 72 male (54.96%) and 59 female (45.04%) fetuses and neonates with mean gestational age of 25.6 weeks. Results showed that small and large intestinal lengths increased linearly with gestational age. RIs for small intestinal length (cm) of fetuses and neonates aged 13-20 weeks were (21.1, 122.4); of those aged 21-28 weeks were (57.7, 203.8); of those aged 29-36 weeks were (83.6, 337.1); and of those aged 37-41 weeks were (132.8, 406.4). RIs for large intestinal length (cm) of fetuses and neonates from the same four age groups were (5.1, 21.4), (12.7, 39.7), (32.4, 62.4), and (29.1, 82.2). Conclusions: Establishing accurate RIs for premature and term infants has clinical relevance for pathologists performing postmortem analysis and for surgeons planning postoperative management of patients. The results of this study reaffirm that fetal small and large intestinal lengths increase linearly with gestational age irrespective of sex. Future studies should aim to further investigate the role of possible confounders on growth of fetal intestinal length, including maternal factors such as age and substance use during pregnancy.

An unusual case of pediatric embryonal rhabdomyosarcoma with subsequent diagnosis of neurofibromatosis type 1.

A 10-month-old girl presented with a 4-month history of a rapidly growing lesion on the lower lip. Initial assessment and Doppler ultrasound supported a diagnosis of pyogenic granuloma. However, emergent biopsy revealed an embryonal rhabdomyosarcoma, a highly malignant tumor commonly associated with cancer-susceptible syndromes including neurofibromatosis type 1 (NF1). Despite having no apparent clinical features of NF1 at initial presentation, she was later found to have multiple café-au-lait spots and a subsequent diagnosis of NF1 was made.

Evaluating the Prognostic Implication of the Collins Histology Scoring System in a Pediatric Eastern Ontario Population With Eosinophilic Esophagitis.

INTRODUCTION: Collins et al developed a histology scoring system (EoE HSS) to assess multiple pathologic features. The aim of this study is to identify if the EoE HSS can better detect endoscopic and symptom improvement vs the Peak Eosinophilic Count (PEC). METHODS: A retrospective chart review was performed for patients during 2014-2016. All patients ≤18 years old with a diagnosis of EoE and whose records included initial and follow-up upper gastrointestinal endoscopies were included. Severity and extent of endoscopic features were scored using 8 parameters, from normal to maximum change for each location of the esophageal biopsy. RESULTS: Forty patients with EoE were included in the study, of which 35 (87.5%) patients demonstrated symptom and 25 (62.5%) endoscopic improvement at the time of follow-up. In the proximal esophagus, the EoE HSS outperformed the change in eosinophil count of the Children's Hospital of Eastern Ontario (CHEO) practice in predicting endoscopic improvement by 16.8% when examining the change in grade and 17.1% when examining the change in stage scores. CONCLUSIONS: At our institution, adoption of the EoE HSS in assessing biopsies of EoE patients might be warranted, compared to the traditional practice. However, a bigger sample size may give a more robust difference in all locations.

ALK-positive histiocytosis: a new clinicopathologic spectrum highlighting neurologic involvement and responses to ALK inhibition.

ALK-positive histiocytosis is a rare subtype of histiocytic neoplasm first described in 2008 in 3 infants with multisystemic disease involving the liver and hematopoietic system. This entity has subsequently been documented in case reports and series to occupy a wider clinicopathologic spectrum with recurrent KIF5B-ALK fusions. The full clinicopathologic and molecular spectra of ALK-positive histiocytosis remain, however, poorly characterized. Here, we describe the largest study of ALK-positive histiocytosis to date, with detailed clinicopathologic data of 39 cases, including 37 cases with confirmed ALK rearrangements. The clinical spectrum comprised distinct clinical phenotypic groups: infants with multisystemic disease with liver and hematopoietic involvement, as originally described (Group 1A: 6/39), other patients with multisystemic disease (Group 1B: 10/39), and patients with single-system disease (Group 2: 23/39). Nineteen patients of the entire cohort (49%) had neurologic involvement (7 and 12 from Groups 1B and 2, respectively). Histology included classic xanthogranuloma features in almost one-third of cases, whereas the majority displayed a more densely cellular, monomorphic appearance without lipidized histiocytes but sometimes more spindled or epithelioid morphology. Neoplastic histiocytes were positive for macrophage markers and often conferred strong expression of phosphorylated extracellular signal-regulated kinase, confirming MAPK pathway activation. KIF5B-ALK fusions were detected in 27 patients, whereas CLTC-ALK, TPM3-ALK, TFG-ALK, EML4-ALK, and DCTN1-ALK fusions were identified in single cases. Robust and durable responses were observed in 11/11 patients treated with ALK inhibition, 10 with neurologic involvement. This study presents the existing clinicopathologic and molecular landscape of ALK-positive histiocytosis and provides guidance for the clinical management of this emerging histiocytic entity.

Porokeratotic eccrine ostial and dermal duct nevus associated with an 11 megabase 3p deletion.

Porokeratotic eccrine ostial and dermal duct nevus (PEODDN) is a rare eccrine hamartoma; the etiology is incompletely understood. A patient presented with congenital, widespread PEODDN. Clinical assessment, histopathologic, cytogenetic, and molecular genetic investigations on affected cells were pursued. Histopathology confirmed PEODDN, and chromosomal microarray on affected tissues identified a mosaic 3p26.3p25.3 deletion in affected tissues. This 11Mb deletion encompasses 47 OMIM genes. We propose that this and other chromosomal deletions may be implicated in some cases of PEODDN, suggesting locus heterogeneity and underscoring the importance of incorporating cytogenetic and molecular investigations into the multidisciplinary care of individuals with suspected mosaic genetic skin disorders.

Examining the Relationship Between Gastroschisis and Placental Fetal Vascular Malperfusion.

INTRODUCTION: Gastroschisis is a congenital malformation characterized by intestinal herniation through an abdominal wall defect. Despite its unknown pathogenesis, known risk factors include maternal smoking, alcohol use, and young maternal age. Previous work has shown that gastroschisis is associated with placental delayed villous maturation, and the goal of this study was to assess for additional associated placental pathologies that may help clarify the pathogenesis of gastroschisis. METHODS: We conducted a retrospective slide review of 29 placentas of neonates with gastroschisis. Additionally, we reviewed pathology reports from one control group of 30 placentas with other congenital malformations. Gross and histological data were collected based on a standardized rubric. RESULTS: Gastroschisis was associated with increased placental fetal vascular malperfusion (FVM) in 62% of cases (versus 0% of controls, p < 0.0001). It was also associated with increased placental villous maldevelopment in 76% of cases (versus 3% of controls, p < 0.0001). CONCLUSION: Our study demonstrates an association between gastroschisis and FVM. While FVM could be the consequence of vascular disruption due to the ventral location of gastroschisis, it could also reflect estrogen-induced thrombosis in early pregnancy. Further research is needed to separate these possibilities and determine the cause of the placental FVM observed in gastroschisis.

Canadian Consensus for Biomarker Testing and Treatment of TRK Fusion Cancer in Pediatric Patients.

Neurotrophic tyrosine receptor kinase gene fusions (NTRK) are oncogenic drivers present at a low frequency in most tumour types (<5%), and at a higher frequency (>80%) in a small number of rare tumours (e.g., infantile fibrosarcoma [IFS]) and considered mutually exclusive with other common oncogenic drivers. Health Canada recently approved two tyrosine receptor kinase (TRK) inhibitors, larotrectinib (for adults and children) and entrectinib (for adults), for the treatment of solid tumours harbouring NTRK gene fusions. In Phase I/II trials, these TRK inhibitors have demonstrated promising overall response rates and tolerability in patients with TRK fusion cancer who have exhausted other treatment options. In these studies, children appear to have similar responses and tolerability to adults. In this report, we provide a Canadian consensus on when and how to test for NTRK gene fusions and when to consider treatment with a TRK inhibitor for pediatric patients with solid tumours. We focus on three pediatric tumour types: non-rhabdomyosarcoma soft tissue sarcoma/unspecified spindle cell tumours including IFS, differentiated thyroid carcinoma, and glioma. We also propose a tumour-agnostic consensus based on the probability of the tumour harbouring an NTRK gene fusion. For children with locally advanced or metastatic TRK fusion cancer who have either failed upfront therapy or lack satisfactory treatment options, TRK inhibitor therapy should be considered.

An aggressive central giant cell granuloma in a pediatric patient: case report and review of literature.

BACKGROUND: Central giant cell granulomas are benign tumours of the mandible, presenting in children and young adults. Divided into non- and aggressive subtypes, the aggressive subtype is relatively rare and can occasionally progress rapidly, resulting in significant morbidity. CASE PRESENTATION: We present a case of an aggressive central giant cell granuloma (CGCG) in a six year-old female. The lesion originated in the right mandibular ramus and progressed rapidly to involve the condyle. Diagnosis was made using a combination of imaging and pathology. A timely en bloc resection of the hemi-mandible was performed with placement of a reconstructive titanium plate and condylar prosthesis. CONCLUSION: Our case demonstrates the importance of considering CGCG in the differential diagnosis of rapidly progressive mandibular lesions in the pediatric population. Prompt diagnosis and management can greatly improve long-term outcomes.

Viable versus nonviable positive margins in Ewing sarcoma and associated recurrence rates: A systematic review.

Residual tumor after curative intent therapy in patients with Ewing's sarcoma is of great clinical significance. Surgeons use the resection margin to indicate the completeness of a surgical excision. However, this margin may be either nonviable/necrotic or viable. This systematic review examines the 5-year event-free survival rate and local recurrence as a function of positive resection margins that are nonviable/necrotic versus those that are viable. Multiple databases were searched using the Ovid interface. After full text screening, 45 articles that reported either margin or postchemotherapy histology and one or more outcomes of interest were identified, and two articles reported on margin and histology simultaneously. An attempt was made to contact the remaining authors and one author was able to provide additional data. The data from the three studies suggest that prognosis in ES depends on both margin involvement and the postchemotherapy histological response simultaneously. However, radiation therapy likely improves local control in patients with inadequate surgical margins, regardless of histological response. This is an area where there is a paucity of evidence that needs to be rectified to ensure that ES patients are provided the highest quality of evidence-based care.

Pilomatrixoma of the ocular adnexa: report of 3 cases with variations in the histopathological findings.

OBJECTIVE: To report the clinical and variations in the histopathological features of pilomatrixoma of the ocular adnexa in 3 young individuals. DESIGN: A retrospective case series was performed with clinical, histological, and immunohistochemical analysis. PARTICIPANTS: Case 1 is an 18-year-old male who presented with a reddish-blue swelling under the left eyebrow. The lesion measured 2 × 1 cm. Case 2 is a 2-year-old female who presented with a reddish-blue nodule inferior to the right eyebrow with telangiectatic vessels. The lesion measured 6 × 4 × 4 mm. Case 3 is a 14-year-old female who presented with a subcutaneous lesion under the right upper eyebrow with fluctuating inflammation. The lesion measured 12 × 3 × 2 mm. Histopathological examination of case 1 disclosed peripheral basaloid cells and central shadow cells containing calcific foci, separated by a transition zone. In case 2, histopathological analysis revealed central calcific foci in islands of shadow cells with more peripheral basaloid cells. In case 3, we observed numerous clusters of shadow cells with focal calcifications, as well as basaloid cells in a disorganized configuration. CONCLUSION: Pilomatrixoma is an uncommon benign skin neoplasm originating from the matrix of the hair root. We describe a spectrum of histopathological findings in pilomatrixoma of the ocular adnexal in 3 young individuals.

Sclerosing Pneumocytoma of the Lungs Arising in a Child With PTEN Mutation.

We report a rare case of sclerosing pneumocytoma occurring in a child with PTEN mutation. A 13-year-old female presented to the emergency department of an adult hospital following 2 to 3 days of upper respiratory tract infection symptoms. A primary lung lesion was discovered during her initial chest X-ray to rule out pneumonia. The patient underwent an uneventful thoracoscopic right upper lobe segmentectomy. The pathology demonstrated a sclerosing pneumocytoma of the lung. She tested positive for PTEN hamartoma tumor syndrome with a pathogenic variant at c.388 C > T. The PTEN mutation was also identified in the sclerosing pneumocytoma. Further study of PTEN mutation in sclerosing pneumocytoma is warranted.

Early Onset Allergic Proctitis in a Preterm Neonate-A Case Report and Review of the Literature.

Cow's milk protein allergy/intolerance (CMPA/CMPI) is a common entity in the pediatric population with a nonspecific presentation ranging from gastrointestinal symptoms to systemic manifestations. Most infants with CMPI are term, and symptoms often appear in the week following the introduction of cow's milk-based formula. There is typically a significant delay in the onset of milk allergy in premature infants compared to full term. We report a rare case of a premature neonate who presented with symptoms of CMPA within the first 2 days of life.

Atypical Hepatic Mesenchymal Hamartoma: Histologic Appearance, Immunophenotype, and Molecular Findings.

Hepatic mesenchymal hamartoma is a rare benign neoplasm principally encountered in young children. Its origin is unknown. We report an unusual hepatic mesenchymal hamartoma in a 7-month-old girl, including histopathologic findings, immunophenotype, and karyotype. Chromosomal microarray analysis of tumoral tissue and circulating lymphocytes found 4 copies of a segment at 1q44 and fluorescence in situ hybridization indicated tandem triplication, ascribed to expansion of a paternal tandem duplication. This genetic abnormality may have played a role in pathogenesis.

Dermal non-neural granular cell tumor in a 3-year-old child.

Dermal non-neural granular cell tumors, also known as primitive polypoid granular cell tumors, are a rare group of distinct cutaneous non-neural granular cell tumors. Pediatric cases are rare, and to the best of our knowledge, we report the youngest patient with dermal non-neural granular cell tumors.

A rare case of pediatric lipoma with t(9;12)(p22;q14) and evidence of HMGA2-NFIB gene fusion.

Lipoma is a benign tumor, typically of adulthood, with characteristic cytogenetic findings, including rearrangement of 12q13-15; these rearrangements often lead to the fusion of the HMGA2 gene at this locus to the transcriptional regulatory domain of its fusion partner, resulting in neomorphic activity that presumably facilitates the neoplastic process. Herein, we report a rare case of pediatric lipoma with t(9;12)(p22;q14) and evidence of HMGA2-NFIB gene fusion in a 9 year-old boy. This case provides further evidence of the link between NFIB rearrangement and early-onset, deep-seated lipomatous tumors.

Pediatric Blastic Plasmacytoid Dendritic Cell Neoplasm: A Systematic Literature Review.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare aggressive hematologic malignancy characterized by frequent skin involvement that most commonly affects older patients. BPDCN is known to have a poor prognosis. Our objective was to assess if outcome and disease prognosis were independently influenced by age when evaluated with clinical presentation, sex, and treatment regimens. We conducted a systematic review to identify BPDCN cases, to compare pediatric BPDCN cases with adult cases. A total of 125 publications were identified detailing 356 cases. Including 1 pediatric case from our institution, 74 were children, and 283 were adults aged 19 or over. Age was shown to be an independent prognostic factor predictive of more favorable outcomes across measures including initial response to therapy, likelihood of relapse, and overall survival at follow-up. The distribution of affected organs at diagnosis was similar across children and adults and type of clinical presentation did not disproportionately influence 1 age group's prognosis over the other. Acute lymphoblastic leukemia-type chemotherapy regimens were shown to be superior to other chemotherapy regimens (acute myeloid leukemia, lymphoma, acute lymphoblastic leukemia/lymphoma, other, or none) in inducing complete remission. Allogeneic stem cell transplantation was shown to increase mean survival time. Future research may be directed toward elucidating the further morphologic, cytogenetic, and cytochemical differences between younger and older BPDCN patients.

Value of upper endoscopic biopsies in predicting medical refractoriness in pediatric patients with ulcerative colitis.

Refractory ulcerative colitis (UC) occurs in patients who experience a severe disease manifestation that is unresponsive to medical therapy. The assessment of upper endoscopic microscopic findings and its correlation with refractory UC has not been fully studied in pediatric patients and is the focus of this study. Medical records of UC patients treated at a tertiary pediatric center between 2000 and 2014 were reviewed. Endoscopic biopsies of the upper gastrointestinal (GI) tract of patients meeting a priori inclusion criteria were compared between refractory UC patients and nonrefractory UC patients for active inflammation. Statistically significant differences were determined between groups, and tissues shown to have significant differences were further evaluated for their diagnostic performance. A total of 52 patients were included, 26 in each group. Significant differences were observed in intraepithelial neutrophil infiltration and percentage involvement of crypts/glands for the antrum, body, and duodenal bulb (P ≤ .001, .005, and .01 [intraepithelial neutrophil infiltration] and P = .001, .009, and .015 [% involvement], respectively). Microabscesses of mucosal glands/crypts were also experienced in a greater number of refractory UC patients in the stomach (ie, antrum and/or body of stomach; P = .005) and duodenum (ie, duodenum and/or duodenal bulb; P = .023). The sensitivity and specificity of upper GI tissues to predict refractory UC were moderate, with sensitivities ranging from 38% to 67% and specificities ranging from 81% to 100%. Our results suggest that children with refractory UC are more likely to have active inflammation in the upper GI tract, and thus, this may represent a predictor of responsiveness to current medical therapy.

Review of Current Applications of Immunohistochemistry in Pediatric Nonneoplastic Gastrointestinal, Hepatobiliary, and Pancreatic Lesions.

Immunohistochemical (IHC) stains are widely used by pathologists for a variety of considerations in the diagnostic workup of pediatric nonneoplastic lesions in gastrointestinal (GI), hepatic, biliary, and pancreatic lesions. The pathologic changes cover a wide range and types of presentations, including inflammatory (bacterial and viral), metaplastic, posttransplant lymphoproliferative, autoimmune, metabolic, degenerative, developmental, and genetic conditions, among others. The everyday practical value of IHC stains covers primary identification, confirmation, differential, and/or exclusionary roles in the hands and eyes and minds of the practitioners. This article is intended to review and discuss the currently available IHC stains for a variety of pediatric GI, hepatobiliary, and pancreatic lesions as encountered in the day-to-day practice of pathologists and clinicians. It reflects the most recent methods and types of IHC stains with the stated aim of helping to provide a quick reference for diagnostic considerations and thereby facilitate the workup of a broad range of GI and related conditions in a pediatric population. The tables provide a handy reference on a wide range of IHC stains for commonly encountered lesions covering a variety of pediatric GI, hepatobiliary, and pancreatic conditions that are amenable to light microscopic diagnostic interpretation.

Update on molecular findings in rhabdomyosarcoma.

Rhabdomyosarcoma (RMS) is the most common malignant soft tissue tumour in children and adolescents. Histologically RMS resembles developing fetal striated skeletal muscle. RMS is stratified into different histological subtypes which appear to influence management plans and patient outcome. Importantly, molecular classification of RMS seems to more accurately capture the true biology and clinical course and prognosis of RMS to guide therapeutic decisions. The identification of PAX-FOXO1 fusion status in RMS is one of the most important updates in the risk stratification of RMS. There are several genes close to PAX that are frequently altered including the RAS family, FGFR4, PIK3CA, CTNNB1, FBXW7, and BCOR. As with most paediatric blue round cell tumours and sarcomas, chemotherapy is the key regimen for RMS therapy. Currently there are no direct inhibitors against PAX-FOXO1 fusion oncoproteins and targeting epigenetic cofactors is limited to clinical trials. Failure of therapy in RMS is usually related to drug resistance and metastatic disease. Through this review we have highlighted most of the molecular aspects in RMS and have attempted to correlate with RMS classification, treatment and prognosis.

Histologic analysis of eosinophils and mast cells of the gastrointestinal tract in healthy Canadian children.

Many gastrointestinal (GI) disorders, including GI eosinophilia and inflammatory bowel disease, can be characterized by increased mucosal eosinophils (EOs) or mast cells (MCs). Normal mucosal cellular counts along the GI tract in healthy children have not been established for a Canadian pediatric population. To establish a benchmark reference, we quantified EO and MC from 356 mucosal biopsies of the GI tract obtained during upper and lower endoscopic biopsies of 38 pediatric patients in eastern Ontario. Mean total counts of EO varied for the 11 tissues we examined, from a low of 7.6±6.5/high-power field (HPF) (×40 [×400, 0.55mm(2)]) in the body of the stomach to a high of 50.3±17.4/HPF in the cecum. The lower GI tract (ileum, cecum, colon, sigmoid, and rectum) generally had higher total EO counts than the upper GI tract (antrum and body of stomach, duodenum, and duodenal cap) (combined average of 32.1±20.6 versus 19.3±15.8, respectively). Similarly, the number of mucosal MC was different in the various regions of the GI tract ranging from 0.04±0.2/HPF in the duodenal cap to 0.9±2.6/HPF in the ileum. Total counts for EO and MC in the lamina propria were not significantly different between sexes when adjusted for multiple testing. EO polarity was absent in many cases, irrespective of the GI region. These numeration and localization of EO and MC will provide normative data for upper and lower endoscopic GI biopsies in the pediatric population of Eastern Ontario.