SOX17-Associated Pulmonary Hypertension in Children: A Distinct Developmental and Clinical Syndrome.

Objective: To characterize clinical, hemodynamic, imaging, and pathologic findings in children with pulmonary arterial hypertension (PAH) and variants in SRY-box transcription factor 17 (SOX17), a novel risk gene linked to heritable and congenital heart disease-associated PAH.

Study Design: We assembled a multi-institutional cohort of children with PAH and SOX17 variants enrolled in the Pediatric Pulmonary Hypertension Network (PPHNet) and other registries. Subjects were identified through exome and PAH gene panel sequencing.

The Pathology of Pulmonary Disease After Pediatric Hematopoietic Stem Cell Transplantation.

Pulmonary complications continue to cause significant morbidity and mortality in posthematopoietic stem cell transplantation (HSCT) settings. The histopathology of pulmonary diseases in the post-HSCT context is poorly characterized, especially in the pediatric population. We sought to characterize the pathologic spectrum of pulmonary disease post-HSCT in a pediatric cohort.

Molecular insights using spatial transcriptomics of the distal lung in congenital diaphragmatic hernia.

Abnormal pulmonary vascular development and function in congenital diaphragmatic hernia (CDH) is a significant factor leading to pulmonary hypertension. The lung is a very heterogenous organ and has marked cellular diversity that is differentially responsive to injury and therapeutic agents. Spatial transcriptomics provides the unmatched capability of discerning the differences in the transcriptional signature of these distinct cell subpopulations in the lung with regional specificity.

Pulmonary Histopathologic Findings in Pediatric Patients After Hematopoietic Stem Cell Transplantation: An Autopsy Study.

Background: Pathologic characterization of pulmonary complications following hematopoietic stem cell transplantation (HSCT) is limited. We describe lung findings in pediatric patients who died following HSCT and attempt to identify potential clinical associations.

Methods: Pathology databases at Texas Children's Hospital and the Children's Hospital of Philadelphia were queried (2013-2018 CHOP and 2017-2018 TCH).

Diffuse alveolar hemorrhage: An underreported complication of transplant associated thrombotic microangiopathy.

Hematopoietic stem cell transplantation-associated thrombotic microangiopathy (TA-TMA) and diffuse alveolar hemorrhage (DAH) are well recognized post-transplant complications that carry a high risk of mortality; however, the risk of DAH complicating the course of transplant patients with TA-TMA is not well understood. We conducted a ten-year retrospective study at our institution to determine the incidence of DAH in a cohort of pediatric patients with TA-TMA and described their presentation and outcomes. Additionally, autopsy slides, when available, were reviewed to assess for histological evidence of microvascular injury and alveolar hemorrhages.

Case Report: The Medical and Surgical Management of an Infant With Extreme Prematurity and Fetus-In-Fetu.

Fetus-in-fetu (FIF) is a rare congenital anomaly where a parasitic twin is within the body of a host twin. FIF is reported to occur in 1:500,000 live births. Herein, we report the first case of the medical and surgical treatment of a FIF patient who was born with extreme prematurity at 25-weeks gestation.

Review of Pediatric Head and Neck Neoplasms that Raise the Possibility of a Cancer Predisposition Syndrome.

Cancer predisposition syndromes (CPS) are generally heritable conditions that predispose individuals to develop cancer at a higher rate and younger age than their representative general population. They are a significant cause of cancer related morbidity and mortality in the pediatric population. Therefore, recognition of lesions that may be associated with a CPS and alerting the clinicians to its implications is a crucial task for a diagnostic pathologist.

Pulmonary Histopathology Findings in Patients With STAT3 Gain of Function Syndrome.

Introduction And Aim: Multiorgan autoimmunity and interstitial lung disease (ILD) are reported in patients with STAT3 GOF syndrome.

Results: We present lung histopathology findings in 3 such children, two of whom underwent wedge biopsies with adequate diagnostic material. Wedge biopsies showed interstitial cellular expansion with linear and nodular aggregates of CD8 positive T lymphocytes, plasma cells, and histiocytes; consistent with lymphocytic interstitial pneumonia pattern (LIP).

Constitutive activation of mitogen-activated protein kinase kinase (MEK1) in ileal enterocytes leads to dysplasia and a predisposition to cancer.

Activation of mitogen-activated protein kinases (MAPKs) is a key factor in the pathogenesis of cancer, although the specific role of mitogen-activated protein kinase kinase (MEK1) is not well understood. Villin promoter-driven Cre expression was used to excise a floxed stop cassette from a phosphomimetically constitutively activated MEK1 (caMEK1) expression construct in the intestine of C57BL/6 mice. Zygosity status of caMEK1 afforded assessment of the dose dependence of the effect.

Endoscopic ultrasound-guided diagnosis of Helicobacter pylori-associated gastric Burkitt's lymphoma in an adolescent patient: a rare case.

Primary gastric Burkitt's lymphoma (BL) is rare in the pediatric population. Furthermore, the association of Burkitt's lymphoma with Helicobacter pylori is not well defined. We report a case of primary gastric Burkitt's lymphoma associated with Helicobacter pylori diagnosed in a pediatric patient.

Lung biopsy in the diagnosis of pediatric ANCA-associated vasculitis.

Objective: To investigate pulmonary histopathologic features in a cohort of pediatric patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) who underwent a lung biopsy as part of their evaluation. We report the safety and the findings of lung biopsies in this population.

Methods: After IRB approval, we performed a retrospective chart review of all patients <18 years of age presenting to our institution with a diagnosis of pediatric AAV (pAAV) who underwent lung biopsy.

Mediastinal Germ Cell Tumor and Acute Megakaryoblastic Leukemia With Co-occurring KRAS Mutation and Complex Cytogenetics.

Young males have a unique but rare predilection to develop mediastinal nonseminomatous germ cell tumors (NSGCTs) and concomitant acute megakaryoblastic leukemia (AMKL). Common cytogenetic and molecular abnormalities such as isochromosome 12p and somatic Tumor Protein P53(TP53) and mutations have been reported in the presumed mutual neoplastic clones of origin. We report the case of a 17-year-old male who presented with a mediastinal NSGCT with high-grade sarcomatous transformation and a diagnosis of AMKL approximately 4 months later.

External Validation of Four Point-of-Care Noninvasive Scores for Predicting Advanced Hepatic Fibrosis in a Predominantly Hispanic NAFLD Population.

Background: The development of point-of-care biomarkers of disease has become a major focus of interest in nonalcoholic fatty liver disease (NAFLD). The NAFLD fibrosis score (NFS), BARD, FIB-4, and aspartate aminotransferase-to-platelet ratio index (APRI) are commonly used for advanced NAFLD fibrosis prediction. However, the performance of these scores among in a predominantly Hispanic patient population, a population with the highest prevalence of NAFLD, has not been examined.

A Rare Case of Vulvar Superficial Angiomyxoma in a Pediatric Patient.

Background: Superficial angiomyxoma (SAM) is a rare, benign cutaneous tumor. Originally described as a component of Carney complex, it is now recognized as a sporadic condition.

Case: A 7-year-old girl was referred for management of a 2.

Hepatic Steatosis Is Prevalent Following Orthotopic Liver Transplantation in Children With Cystic Fibrosis.

Objectives: Systematic study of allograft liver histology in children undergoing orthotopic liver transplantation (LT) for cystic fibrosis-related liver disease (CFLD).

Methods: Retrospective clinicopathologic review of explants and allograft liver biopsies from 13 children and adolescents with CFLD.

Results: In this study, the median age at LT for CFLD was 15.

Translocation t(7;12) as the sole chromosomal abnormality resulting in ACTB-GLI1 fusion in pediatric gastric pericytoma.

We hereby report an unusual gastric tumor arising from the pyloric wall of the stomach in a 9-year-old child harboring the exceptionally rare translocation t(7;12) resulting in ACTB-GLI1 gene fusion. This tumor has been previously classified as pericytoma with t(7;12) and described in 6 patients, 2 of them children. We discuss the challenges in recognizing this rare entity and the importance of the molecular studies in establishing the correct diagnosis.

Soluble Tie2 overrides the heightened invasion induced by anti-angiogenesis therapies in gliomas.

Glioblastoma recurrence after treatment with the anti-vascular endothelial growth factor (VEGF) agent bevacizumab is characterized by a highly infiltrative and malignant behavior that renders surgical excision and chemotherapy ineffective. Our group has previously reported that Tie2-expressing monocytes (TEMs) are aberrantly present at the tumor/normal brain interface after anti-VEGF therapies and their significant role in the invasive outgrowth of these tumors. Here, we aimed to further understand the mechanisms leading to this pro-invasive tumor microenvironment.

Macrophage Ablation Reduces M2-Like Populations and Jeopardizes Tumor Growth in a MAFIA-Based Glioma Model.

Monocytes/macrophages are an influential component of the glioma microenvironment. However, understanding their diversity and plasticity constitute one of the most challenging areas of research due to the paucity of models to study these cells' inherent complexity. Herein, we analyzed the role of monocytes/macrophages in glioma growth by using a transgenic model that allows for conditional ablation of this cell population.

Anti-vascular endothelial growth factor therapy-induced glioma invasion is associated with accumulation of Tie2-expressing monocytes.

The addition of anti-angiogenic therapy to the few treatments available to patients with malignant gliomas was based on the fact that these tumors are highly vascularized and on encouraging results from preclinical and clinical studies. However, tumors that initially respond to this therapy invariably recur with the acquisition of a highly aggressive and invasive phenotype. Although several myeloid populations have been associated to this pattern of recurrence, a specific targetable population has not been yet identified.