Proteomic Profiling of Hypoplastic Lungs Suggests an Underlying Inflammatory Response in the Pathogenesis of Abnormal Lung Development in Congenital Diaphragmatic Hernia.

The pathogenesis of lung hypoplasia in congenital diaphragmatic hernia (CDH), a common birth defect, is poorly understood. The diaphragmatic defect can be repaired surgically, but the abnormal lung development contributes to a high mortality in these patients. To understand the underlying pathobiology, we compared the proteomic profiles of fetal rat lungs at the alveolar stage (E21) that were either exposed to nitrofen in utero (CDH lungs, n=5) or exposed to vehicle only (non-CDH control lungs, n=5). Pathway analysis of proteomic datasets showed significant enrichment in inflammatory response proteins associated with cytokine signaling and Epstein Barr Virus in nitrofen CDH lungs. Among the 218 significantly altered proteins between CDH and non-CDH control lungs were Tenascin C, CREBBP, LYN, and STAT3. We showed that Tenascin C was decreased around the distal airway branches in nitrofen rat lungs and human CDH lungs, obtained from stillborn fetuses that did not receive pre- or postnatal treatment. In contrast, STAT3 was significantly increased in the airway epithelium of nitrofen lungs at E21. STAT3 inhibition after direct nitrofen exposure to fetal rat lung explants (E14.5) partially rescued the hypoplastic lung phenotype ex vivo by increasing peripheral lung budding. Moreover, we demonstrated that several STAT3-associated cytokines (IL-15, IL-9, andIL-2) are increased in fetal tracheal aspirates of CDH survivors compared with nonsurvivors after fetoscopic endoluminal tracheal occlusion. With our unbiased proteomics approach, we showed for the first time that downstream inflammatory processes are likely involved in the pathogenesis of abnormal lung development in CDH.

Workload Measurement in Subspecialty Placental Pathology in Canada.

BACKGROUND: Workload measurement is important to help determine optimal staffing and workload distribution for pathology laboratories. The Level 4 Equivalent (L4E) System is the most widely used Anatomical Pathology (AP) workload measurement tool in Canada. However, it was initially not developed with subspecialties in mind. METHODS: In 2016, a Pan-Canadian Pediatric-Perinatal Pathology Workload Committee (PCPPPWC) was organized to adapt the L4E System to assess Pediatric-Perinatal Pathology workload. Four working groups were formed. The Placental Pathology Working Group was tasked to develop a scheme for fair valuation of placental specimens signed out by subspecialists in the context of the L4E System. Previous experience, informal time and motion studies, a survey of Canadian Pediatric-Perinatal Pathologists, and interviews of Pathologists' Assistants (PA) informed the development of such scheme. RESULTS: A workload measurement scheme with average L4E workload values for examination and reporting of singleton and multiple gestation placentas was proposed. The proposal was approved by the Canadian Association of Pathologist - Association canadienne des pathologistes Workload and Human Resources Committee for adoption into the L4E System. CONCLUSION: The development of a workload measurement model for placental specimens provides an average and fair valuation of these specimen types, enabling its use for resource planning and workload distribution.

Thromboangiitis Obliterans (Buerger's Disease) in an Adolescent Male.

Arterial occlusive disease of the limb is very rare in children. Buerger's disease (BD) is a nonatherosclerotic, segmental inflammatory arteritis affecting the small and medium-sized vessels of the extremities. We report BD in a 16-year-old male presenting with arterial insufficiency of left foot and history of smoking cigarettes and cannabis for 2 years. BD was diagnosed based on history of smoking in combination with clinical, laboratory, and radiologic findings. Pediatric hemato-oncologists should consider BD in the differential diagnosis in adolescents who smoke cigarettes and/or cannabis and present with vascular insufficiency of the hands and/or feet.

Epithelial cell-adhesion protein cadherin 26 is dysregulated in congenital diaphragmatic hernia and congenital pulmonary airway malformation.

BACKGROUND: Congenital diaphragmatic hernia (CDH) and congenital pulmonary airway malformation (CPAM) are two inborn pathologies of the lung of unknown origin. Alterations of gene expression in airway epithelial cells are involved in the pathobiology of both diseases. We previously found decreased expression of the epithelial cell adhesion protein cadherin 26 (CDH26) in hypoplastic mice lungs. Here, our objective was to describe the expression and localization of CDH26 in hypoplastic CDH lungs and hyperproliferative CPAM tissues. METHODS: After ethical approval, we used human lung tissues from CDH and CPAM cases and age-matched control samples from a previously established biobank. Furthermore, lungs from the nitrofen rat model of CDH were included in the study. We performed immunohistochemistry and western blot analysis with antibodies against CDH26 to examine protein localization and abundance. Statistical analysis was performed using Mann-Whitney U test with significance set at p < 0.05. RESULTS: We observed an overexpression of CDH26 within the epithelium of cystic CPAM lesions compared to normal airways within the same lung and compared to control lungs. Western blot demonstrated a downregulation of CDH26 in the nitrofen rat model of CDH compared to healthy controls. Immunohistochemistry could not show consistent differences between CDH and control in human and rat lungs. In the studied human lung samples, CDH26 was localized to the apical part of the airway epithelial cells. CONCLUSION: CDH26 is differentially expressed in human CPAM lung tissues and may be downregulated in nitrofen-induced hypoplastic rat lungs compared to control lungs. Disruption of CDH26 associated pathways in lung development may be involved in the pathogenesis of lung hypoplasia or cystic lung disease.

Disseminated Echinococcus multilocularis Infection without Liver Involvement in Child, Canada, 2018.

An immunocompetent child in Canada received a diagnosis of disseminated alveolar Echinococcus multilocularis infection. The case lacked typical features of liver involvement and was possibly related to a rare congenital portosystemic shunt. We summarize the rapidly evolving epidemiology of E. multilocularis parasites in Canada.

Detection of Cytomegalovirus in Colonic Mucosa of Children With Inflammatory Bowel Disease: Inflammatory Bowel Disease.

OBJECTIVES: Although it has been recommended to perform sigmoidoscopy to screen for cytomegalovirus (CMV) reactivation in acute severe colitis, the frequency of CMV reactivation in children with inflammatory bowel disease (IBD) is unknown. The aim of this study was to determine the frequency and management of CMV detection in colonic mucosa of children with IBD. METHODS: In a retrospective study, consecutive IBD patients, <17 years old, with moderate to severe colitis who had sigmoid biopsy specimens evaluated for CMV by hematoxylin and eosin (H&E) staining, immunohistochemistry (IHC), and polymerase chain reaction (PCR) were included. RESULTS: A total of 90 sigmoid biopsies were collected from 67 patient encounters from 58 patients with colitis: 61 patient encounters (91%) with UC/IBD-U including biopsy samples from colectomy specimens of eight patients who had colectomy during the study period. Medication exposure included corticosteroids for 40 (69%) patients, and immunosuppressive agents for 31 (53.4%) patients. Four of 61 patient encounters (6.6%) with UC/IBD-U, two with corticosteroid refractory disease, had positive biopsies for CMV by PCR but negative H&E and IHC. They responded to escalated medical therapy, without needing anti-viral therapy, and none required colectomy over a median duration of follow up of 1.1 year (IQR 1-1.6). CONCLUSIONS: CMV presence is uncommon in colonic mucosa of children with IBD. Studies examining the underlying sero-prevalence of CMV and its role of reactivation of colitis are required to determine if the current recommendation for routine sigmoidoscopy to exclude CMV infection in corticosteroid-refractory acute severe colitis is justified.

Transplantation-associated thrombotic microangiopathy isolated to a congenital anomaly of the lung.

TA-TMA is a post-hematopoietic stem cell transplant complication with clinical features of hemolytic anemia and thrombocytopenia. A 26-month-old child who had had an allogeneic transplant for treatment of DBA developed severe TA-TMA with heavy red blood cell and platelet transfusion dependence. Incidentally, he was found to have a lung sequestration. TA-TMA resolved and transfusion dependence resolved after resection of the sequestration. The finding suggests the malformation vasculature was selectively vulnerable to the trigger of TA-TMA-raising perhaps a clue to basic pathophysiology of TA-TMA and/or vascular malformations.

Prevalence of Peripheral Eosinophilia at Diagnosis in Children With Inflammatory Bowel Disease.

BACKGROUND AND OBJECTIVE: Inflammatory bowel disease (IBD) encompasses 2 disorders of unknown etiology: Crohn disease (CD) and ulcerative colitis (UC). There has been a continuous search for markers for disease activity. Eosinophils are granulocytic leukocytes that are implicated in the pathogenesis of IBD. The aim of this study was to examine the prevalence and significance of peripheral eosinophilia (PE) at diagnosis in children with IBD. METHODS: A comprehensive chart review of all children with diagnosed as having IBD between January 2006 and August 2014 was performed. Patients with PE at diagnosis were compared with those without in relation to disease clinical activity and disease course. RESULTS: A total of 109 children (mean age 14.6 ± 2.77, range 4.5-17.9 years, 55 boys) with IBD (68 with CD and 41 with UC) who were studied for a mean duration of 2.82 ± 1.89 (range 0.1-9.2 years) were identified. At diagnosis, 44 (40.4%) children had PE, which was more prevalent in patients with UC compared with those with CD (61.3% vs 36.3%, P < 0.05). At diagnosis, PE was more common in patients with high eosinophilic count in colonic biopsy samples (P < 0.01) and was significantly associated with disease activity as indicated by Pediatric CD Activity Index for children with CD (P < 0.05), Pediatric UC Activity Index for children with UC (P < 0.01). CONCLUSIONS: PE is a common finding at diagnosis in children with IBD especially in those with UC. Patients with PE at diagnosis are more likely to present with higher clinical activity indices. PE is associated with more eosinophils in colonic biopsy samples.

Aggressive Metastatic Inflammatory Myofibroblastic Tumor After Allogeneic Stem Cell Transplant With Fatal Pulmonary Toxicity From Crizotinib.

Inflammatory myofibroblastic tumors (IMTs) are rare tumors with an intermediate spectrum of biological behavior. IMTs are uncommon secondary malignancies after hematopoietic stem cell transplant. The presence of anaplastic lymphoma kinase rearrangements in 50% of IMTs has led to therapeutic trials with crizotinib, although limited experience remains with crizotinib use in children. We describe the first reported case of a highly aggressive and metastatic IMT (secondary malignancy) in an 8-year-old girl following umbilical cord blood transplant. Although tumor response was demonstrated with anaplastic lymphoma kinase inhibition, she later developed fatal pulmonary toxicity from diffuse alveolar damage, a feature felt most likely to be due to crizotinib.

A homozygous PMS2 founder mutation with an attenuated constitutional mismatch repair deficiency phenotype.

BACKGROUND: Inherited mutations in DNA mismatch repair genes predispose to different cancer syndromes depending on whether they are mono-allelic or bi-allelic. This supports a causal relationship between expression level in the germline and phenotype variation. As a model to study this relationship, our study aimed to define the pathogenic characteristics of a recurrent homozygous coding variant in PMS2 displaying an attenuated phenotype identified by clinical genetic testing in seven Inuit families from Northern Quebec. METHODS: Pathogenic characteristics of the PMS2 mutation NM_000535.5:c.2002A>G were studied using genotype-phenotype correlation, single-molecule expression detection and single genome microsatellite instability analysis. RESULTS: This PMS2 mutation generates a de novo splice site that competes with the authentic site. In homozygotes, expression of the full-length protein is reduced to a level barely detectable by conventional diagnostics. Median age at primary cancer diagnosis is 22 years among 13 NM_000535.5:c.2002A>G homozygotes, versus 8 years in individuals carrying bi-allelic truncating mutations. Residual expression of full-length PMS2 transcript was detected in normal tissues from homozygotes with cancers in their 20s. CONCLUSIONS: Our genotype-phenotype study of c.2002A>G illustrates that an extremely low level of PMS2 expression likely delays cancer onset, a feature that could be exploited in cancer preventive intervention.

Obstructed Hemivagina and Ipsilateral Renal Anomaly (OHVIRA) - A Fetal Autopsy Case.

BACKGROUND: Obstructed hemivagina and ipsilateral renal anomaly (OHVIRA) is a rare congenital anomaly characterized by uterus didelphys, unilateral obstructed hemivagina, and ipsilateral renal anomaly. CASE: Autopsy performed on a third trimester stillborn fetus unexpectedly revealed uterine didelphys, an obstructed left hemivagina, and a left pelvic, atrophic, duplex kidney, with both left ureters entering the obstructed left hemivagina. Furthermore, the fetus had an imperforate anus, a single right umbilical artery, and spina bifida occulta. SUMMARY AND CONCLUSION: Although rare, OHVIRA is a well-documented congenital anomaly. However, prior to this case, there had been no description of OHVIRA in an autopsy or in a fetus. Furthermore, the association of OHVIRA, anorectal malformation, and spinal bifida has never been reported. By sharing this case, we hope to increase the awareness of this entity among perinatal healthcare providers and to help further elucidate genitourinary embryology, which is still not fully understood.

Establishment of a biobank for human lung tissues of congenital diaphragmatic hernia and congenital pulmonary airway malformation.

BACKGROUND: Human tissue samples are an invaluable and little available source of information for translational studies of congenital lung diseases such as Congenital Diaphragmatic Hernia (CDH) or Congenital Pulmonary Airway Malformation (CPAM). PURPOSE: We aimed to establish a human lung tissue biobank of CDH and CPAM patients together with age-matched controls, coupled with a clinical database. METHODS: Pathology records from autopsies or surgical specimens for CDH and CPAM cases between 1980 and 2017 were reviewed. For surviving individuals, clinical patient data was obtained from corresponding pediatric surgery reports. Formalin-fixed, paraffin-embedded tissues of patients and age-matched controls were systematically stored for further translational studies. RNA integrity was determined on selected CDH blocks. RESULTS: A total of 16 CDH and 18 CPAM and age-matched control lung tissue blocks were included in our biobank. Ages ranged from 22 to 41 weeks of gestation (GA) in CDH (33.9 ±â€¯6.35 weeks) and 26 weeks (GA) and 12 years in CPAM (2.3 ±â€¯3.7 y). RNA isolation from CDH and control blocks yielded good RNA quality (OD 260/280 ratio: 2.01-2.09, OD 260/230 ratio: 2.04-2.09). CONCLUSION: We established a unique human biobank for CDH and CPAM tissues. The combination with clinical patient data will allow us to design future translational studies to improve our understanding of the disease pathogenesis of these congenital malformations.

Colonic Abnormalities in Manitoban Children with Helicobacter pylori Gastritis.

OBJECTIVES: Association between Helicobacter pylori (H. pylori) and colonic pathology is underinvestigated. The aim of this work was to examine the prevalence and nature of colonic changes in children diagnosed with H. pylori gastritis. METHODS: A comprehensive retrospective review of the medical records for all Manitoban children (≤17 years) diagnosed with H. pylori gastritis from January 1996 to May 2015 was conducted. Children with H. pylori gastritis who had colonoscopy were identified. Patients' demographics, indications for colonoscopy, laboratory and endoscopic findings, and colonic histopathological abnormalities were documented. RESULTS: A total of 231 children were found to have H. pylori gastritis. The mean age at diagnosis was 12.3 ± 4.1 years; 108 (46.6%) were girls. Of the 231 patients, 37 (16%) patients were found to have colonoscopy performed. Indications for colonoscopy included bleeding per rectum, significant weight loss, and hypoalbuminemia. Twenty-two (59%) of 37 children who had colonoscopy had significant endoscopic and histopathological findings on colonoscopy including polyposis and colitis. Boys with colonic changes were diagnosed at an earlier age compared to those without (11.5 ± 7.0 versus 15.0 ± 2.0, p < 0.049). CONCLUSIONS: Our study may suggest a possible association between H. pylori and a subset of colonic changes in children.

Intracranial atypical teratoid/rhabdoid tumor presenting as an axillary mass: a case report and review of literature.

Atypical teratoid/rhabdoid tumor (AT/RT) is an uncommon, high-grade pediatric malignancy of the central nervous system (CNS) that rarely metastasizes outside the CNS (Chang stage M4). We describe a child with the sole metastasis of an AT/RT to an axillary lymph node and no other site of extra-CNS disease at presentation. The tumor included areas of rhabdoid cells and failed to express the SMARCB1 gene product (INI1). The metastatic site in this patient is unusual for 3 reasons: (1) it is anatomically unexpected for a CNS tumor, (2) no other extra-CNS metastasis or primary tumor outside the CNS was found, and (3) no cardiac septal defect or vascular anomaly was identified. This site as the presenting lesion and sole metastasis of an intracranial AT/RT has not been previously reported. We attempt to explain this phenomenon.

Myxoinflammatory fibroblastic sarcoma in children and adolescents: clinicopathologic aspects of a rare neoplasm.

Myxoinflammatory fibroblastic sarcoma (MIFS), originally described as a low-grade malignant soft-tissue tumor in adults, has recently been reported in children and in non-acral sites. This report describes the clinicopathologic features of a series of 5 MIFS in children and adolescents (3 males, 2 females), ranging in age from 5 to 17 years (mean, 13 years). These tumors presented as small, superficial, slowly growing soft-tissues masses of the scalp, neck, middle finger, forearm, and thigh. Histologically, the tumors were composed of spindled and plump polygonal cells with prominent nuclear pleomorphism, nuclear pseudoinclusions; large eosinophilic nucleoli; myxoid foci intermingled with spindled foci; and an accompanying inflammatory infiltrate of lymphocytes, plasma cells, and variable neutrophils. Immunohistochemical analysis revealed variable reactivity for CD34 and smooth muscle actin in the tumor cells. Genetic analysis in 3 cases showed no rearrangements of TGFBR3 or MGEA5. Follow up in 4 cases revealed no recurrence or metastasis. These 5 cases of childhood and adolescent MIFS demonstrate an expanded age range and topographic distribution and a favorable outcome. The differential diagnosis and importance of recognizing this rare neoplasm in young patients are discussed.