Histopathology of Eosinophilic Esophagitis.

Microscopic examination of esophageal biopsies is essential to diagnose eosinophilic esophagitis (EoE). Eosinophil inflammation is the basis for the diagnosis, but additional abnormalities may contribute to persistent symptoms and epithelial barrier dysfunction. Both peak eosinophil count and assessments of additional features should be included in pre-therapy and post-therapy pathology reports. Pathologic abnormalities identified in esophageal biopsies of EoE are reversible in contrast to esophageal strictures.

Histopathology of Eosinophilic Gastrointestinal Diseases Beyond Eosinophilic Esophagitis.

Eosinophilic gastrointestinal diseases (EGID), such as eosinophilic gastritis (EoG), eosinophilic enteritis, and eosinophilic colitis (EoC), are chronic inflammatory conditions characterized by persistent gastrointestinal symptoms and elevated levels of activated eosinophils in the gastrointestinal tract. EoG and eosinophilic duodenitis (EoD) are strongly associated with food allergen triggers and TH2 inflammation, whereas EoC shows minimal transcriptomic overlap with other EGIDs. The level of expression of certain genes associated with TH2 immune response is associated with certain histopathologic findings of EoG, EoD, and EoC. Current immune therapy for EoG depletes tissue eosinophilia with persistence of other histopathologic features of disease.

Induced pluripotent stem cell (iPSC) modeling validates reduced GBE1 enzyme activity due to a novel variant, p.Ile694Asn, found in a patient with suspected glycogen storage disease IV.

Background: Glycogen Storage disease type 4 (GSD4), a rare disease caused by glycogen branching enzyme 1 (GBE1) deficiency, affects multiple organ systems including the muscles, liver, heart, and central nervous system. Here we report a GSD4 patient, who presented with severe hepatosplenomegaly and cardiac ventricular hypertrophy. GBE1 sequencing identified two variants: a known pathogenic missense variant, c.1544G>A (p.Arg515His), and a missense variant of unknown significance (VUS), c.2081T>A (p. Ile694Asn). As a liver transplant alone can exacerbate heart dysfunction in GSD4 patients, a precise diagnosis is essential for liver transplant indication. To characterize the disease-causing variant, we modeled patient-specific GBE1 deficiency using CRISPR/Cas9 genome-edited induced pluripotent stem cells (iPSCs). Methods: iPSCs from a healthy donor (iPSC-WT) were genome-edited by CRISPR/Cas9 to induce homozygous p.Ile694Asn in GBE1 (iPSC-GBE1-I694N) and differentiated into hepatocytes (iHep) or cardiomyocytes (iCM). GBE1 enzyme activity was measured, and PAS-D staining was performed to analyze polyglucosan deposition in these cells. Results: iPSCGBE1-I694N differentiated into iHep and iCM exhibited reduced GBE1 protein level and enzyme activity in both cell types compared to iPSCwt. Both iHepGBE1-I694N and iCMGBE1-I694N showed polyglucosan deposits correlating to the histologic patterns of the patient's biopsies. Conclusions: iPSC-based disease modeling supported a loss of function effect of p.Ile694Asn in GBE1. The modeling of GBE1 enzyme deficiency in iHep and iCM cell lines had multi-organ findings, demonstrating iPSC-based modeling usefulness in elucidating the effects of novel VUS in ultra-rare diseases.

Intrahepatic Cholangiolitis in Cystic Fibrosis (ICCF): An Under-Appreciated Cause of Persistent Cholestasis in Infancy.

Liver histology in infants with cystic fibrosis (CF) and persistent cholestasis is seldom reported in detail. We extend previous observation of a distinctive intrahepatic cholangiopathy (ICCF) to 3 additional infants homozygous for CFTR pathological variants and a fourth infant with a heterozygous CFTR variant, summarizing our experience in 10 infants with CFTR variants and persistent cholestasis. Cholangiograms demonstrate abnormal extrahepatic ducts in 2 infants with CF, 1 with uniform dilatation interpreted as a choledochal cyst and the other with narrow patent ducts. Liver histology in 3 CF homozygotes had prominent ductular reaction with a focally destructive cholangiolitis (inflammation of small bile ducts). The CFTR heterozygote had generalized portal edema with ductular reaction and paucity but no cholangitis. Cholestasis slowly subsided in all infants. ICCF is characterized by severe ductular reaction, prominent cholangiocyte injury, and multifocal necrotizing cholangiolitis. Local aggregates of portal ceroid might suggest previous bile leakage from damaged ducts. ICCF in liver biopsies from infants with cystic fibrosis and persistent cholestasis is unrelated to the specific CFTR genotype. Liver biopsy findings and intraoperative cholangiogram help rule out biliary atresia. ICCF is an early manifestation of CF, a likely prototype for pathogenesis of cystic fibrosis liver disease later in life.

Kruppel-like factor 2+ CD4 T cells avert microbiota-induced intestinal inflammation.

Intestinal colonization by antigenically foreign microbes necessitates expanded peripheral immune tolerance. Here we show commensal microbiota prime expansion of CD4 T cells unified by the Kruppel-like factor 2 (KLF2) transcriptional regulator and an essential role for KLF2+ CD4 cells in averting microbiota-driven intestinal inflammation. CD4 cells with commensal specificity in secondary lymphoid organs and intestinal tissues are enriched for KLF2 expression, and distinct from FOXP3+ regulatory T cells or other differentiation lineages. Mice with conditional KLF2 deficiency in T cells develop spontaneous rectal prolapse and intestinal inflammation, phenotypes overturned by eliminating microbiota or reconstituting with donor KLF2+ cells. Activated KLF2+ cells selectively produce IL-10, and eliminating IL-10 overrides their suppressive function in vitro and protection against intestinal inflammation in vivo. Together with reduced KLF2+ CD4 cell accumulation in Crohn's disease, a necessity for the KLF2+ subpopulation of T regulatory type 1 (Tr1) cells in sustaining commensal tolerance is demonstrated.

Esophageal Granular Cell Tumor in Children: A Clinicopathologic Study of 11 Cases and Review of the Literature.

OBJECTIVES: Granular cell tumor (GCT) commonly presents in the subcutaneous tissue and head and neck region, and it is uncommon in the gastrointestinal tract. Experience with esophageal GCTs in the pediatric population is limited, with only 7 cases reported in the literature, 3 with eosinophilic esophagitis (EoE). METHODS: Case information from 11 pediatric patients with GCTs of the esophagus was retrieved. H&E and immunohistochemical slides were reviewed with clinical, endoscopic, and follow-up data from all patients. RESULTS: In total, 7 male and 4 female patients were included, with ages ranging from 3 to 14 years. Indications for esophagogastroduodenoscopy (EGD) included EoE (n = 3), follow-up for Crohn disease, and other nonspecific complaints. Endoscopically, all patients had a single submucosal, firm mass protruding into the lumen, with normal overlying mucosa. The nodules were removed endoscopically in multiple fragments in all cases. Histologically, the tumors showed sheets and trabeculae of cells containing bland nuclei, inconspicuous nucleoli, and abundant pink granular cytoplasm without atypical features. All tumors were immunoreactive for S100, CD68, and SOX10. Follow-up showed that all patients were disease-free (median, 2 years). CONCLUSIONS: We report the largest series of pediatric esophageal GCTs with coincidental association with EoE. These EGD findings are characteristic, and removal by biopsy is both diagnostic and therapeutic.

Using Human Induced Pluripotent Stem Cell-Derived Organoids to Identify New Pathologies in Patients With PDX1 Mutations.

BACKGROUND & AIMS: Two patients with homozygous mutations in PDX1 presented with pancreatic agenesis, chronic diarrhea, and poor weight gain, the causes of which were not identified through routine clinical testing. We aimed to perform a deep analysis of the stomach and intestine using organoids derived from induced pluripotent stem cells from PDX1188delC/188delC patients. METHODS: Gastric fundic, antral, and duodenal organoids were generated using induced pluripotent stem cell lines from a PDX1188delC/188delC patient and an isogenic induced pluripotent stem cell line where the PDX1 point mutation was corrected. RESULTS: Patient-derived PDX1188delC/188delC antral organoids exhibited an intestinal phenotype, whereas intestinal organoids underwent gastric metaplasia with significant reduction in enteroendocrine cells. This prompted a re-examination of gastric and intestinal biopsy specimens from both PDX1188delC/188delC patients, which recapitulated the organoid phenotypes. Moreover, antral biopsy specimens also showed increased parietal cells and lacked G cells, suggesting loss of antral identity. All organoid pathologies were reversed upon CRISPR-mediated correction of the mutation. CONCLUSIONS: These patients will now be monitored for the progression of metaplasia and gastrointestinal complications that might be related to the reduced gastric and intestinal endocrine cells. This study demonstrates the utility of organoids in diagnosing uncovered pathologies.

Pitfalls of iron supplementation in parenteral nutrition admixtures for children with intestinal failure.

BACKGROUND: Pediatric patients with intestinal failure are at increased risk for iron deficiency. Supplementation is not routinely included in parenteral nutrition solutions. There is currently limited research related to the safety of iron supplementation in parenteral nutrition and for intravenous forms used in patients with intestinal failure. Current American Society for Parenteral and Enteral Nutrition and ESPGHAN guidelines promote the use of enteral iron, acknowledging the risks of using iron supplementation within parenteral nutrition admixtures. METHODS: We review a patient case and the current available literature related to iron in parenteral nutrition. RESULTS: Five major concerns are identified: peroxidation reactions, incompatibility, hypersensitivity, infection risk, and iron overload. CONCLUSION: We propose an argument against the preferential use of iron supplementation within parenteral nutrition in children with intestinal failure when enteral supplementation or intermittent parenteral infusion may be sufficient.

Cranial Fasciitis in Children: Expanding the Spectrum of USP6-Associated Clonal Transient Neoplasms.

Background: Cranial fasciitis (CF) is a benign (myo)fibroblastic proliferation of children. Typical presentation consists of a rapidly growing solitary mass on the temporal or parietal cranium in the first 2 years of age. CF is characterized by a rapid growth followed by a relative slowdown and even growth arrest. The finding of somatic USP6 gene rearrangements demonstrating clonality in CF together with its clinical behavior places it in the category of diseases recently termed "transient neoplasia."Methods: Histological, immunohistochemical, and molecular findings of 18 patients with CF were retrospectively studied.Results: The tumor typically presented as a painless rapidly enlarging mass in the temporal region. Sixty-six percent of the cases harbored USP6 gene rearrangement. Nine patients were treated with gross total resection (GTR) and 9 with subtotal tumor resection (STR). Two patients treated with GTR had recurrence. Five patients treated with STR had progression-free disease for at least 10 months after surgery and in four patients the tumor regressed spontaneously a median 16 months after surgery.Conclusions: In this largest series to date, we reported the clinicopathological, immunohistochemical, and molecular findings of 18 pediatric cases of CF with emphasis on the clinical growth pattern of these tumors.

Critical diagnoses in paediatric gastrointestinal diseases.

Gastrointestinal biopsies represent an increasing proportion of the paediatric pathologist's workload, an increase fundamentally due to an expansion of the understanding of the basic clinical, molecular, genetic, and histopathological features of paediatric gastrointestinal disorders. The histological interpretation of endoscopically retrieved gastrointestinal biopsies in children requires a unique set of diagnostic expertise and detailed knowledge of various gastrointestinal disorders that have a predilection for the paediatric population. This article's major role is to highlight the unique problems inherent to paediatric gastrointestinal disorders that require immediate communication with the paediatric surgeon or the gastroenterologist. For this, we tried to cover the most important diseases that a paediatric pathologist might encounter in daily practice. Some of these diseases are relatively rare, such as microvillous inclusion disease and tufting enteropathy, but some are more common such as eosinophilic disorders and inflammatory bowel disease. Awareness of the histopathological features of these diseases, particularly those that are relatively uncommon, is crucial to spare the patient a lengthy and costly evaluation. We made a particular effort to abundantly reference this article should the reader wish to expand on the content of any section.

Hypoplasia of Extrahepatic Biliary Tree and Intrahepatic Cholangiolopathy in Cystic Fibrosis Imperfectly Mimic Biliary Atresia in 4 Infants With Cystic Fibrosis and Kasai Portoenterostomy.

Four male infants with cystic fibrosis and prolonged neonatal jaundice underwent Kasai procedure to relieve biliary obstruction due to apparent biliary atresia. The excised remnants had viscid mucus accumulation in hypoplastic gallbladders and distended peribiliary glands. Main hepatic ducts were narrow and/or malformed. Microscopic differences between the gallbladder and extrahepatic bile ducts in cystic fibrosis and sporadic biliary atresia were unequivocal, despite some histologic overlap; no erosive or fibro-obliterative lesions typical of biliary atresia were seen. Common in liver, biopsies were small duct cholangiopathy with intense focal cholangiolitis and massive accumulation of ceroid pigment within damaged cholangiocytes, and in portal macrophages, portal fibrosis, and unequivocal features of large duct obstruction were inconspicuous compared with biliary atresia. Plugs of bile in small ducts tended to be pale and strongly periodic acid-Schiff-reactive in cystic fibrosis. Distinguishing the liver lesion from that of biliary atresia is challenging but possible. Liver biopsies from 2 additional infants with cystic fibrosis and prolonged jaundice that spontaneously resolved showed a similar small duct cholangiopathy. Small gallbladders and extrahepatic ducts challenge surgical judgment as findings in liver biopsies challenge the pathologist. The decision to perform a Kasai procedure is reasonable when mimicry of biliary atresia is grossly complete. We hypothesize that a disorder of bile volume/flow during development and/or early infancy linked to the CFTR mutation alone or in combination with the stresses of neonatal intensive care causes destructive cholangiolitis and intrahepatic reduction of bile flow with secondary hypoplasia of extrahepatic biliary structures.

Clinicopathologic Correlations in Eosinophilic Gastrointestinal Disorders.

Eosinophilic gastrointestinal disorders (EGIDs) are a collection of disorders characterized by allergy-driven inflammation of the gastrointestinal (GI) tract. Affected patients typically present with nonspecific symptoms of GI dysfunction and are frequently found to have mucosal abnormalities during endoscopy as well as increased eosinophil levels on tissue biopsy that are felt to be responsible for generating the clinical findings. Each of these findings is important in both the diagnosis and management of EGIDs. Understanding the impact of histopathologic and endoscopic changes on clinical signs and symptoms is critical to developing an understanding of the natural history of these disorders as well as to the generation of validated assessment tools and targeted therapies. We explore these relationships in this review.

Incomplete resection of necrotic bowel may increase mortality in infants with necrotizing enterocolitis.

BACKGROUND: Infants with advanced necrotizing enterocolitis (NEC) often need surgical resection of necrotic bowel. We hypothesized that incomplete resection of NEC lesions, signified by the detection of necrotic patches in margins of resected bowel loops, results in inferior clinical outcomes. METHODS: We reviewed the medical records of infants with surgical NEC in the past 15 years for demographic, clinical, and histopathological data. We also developed statistical models to predict mortality and hospital stay. RESULTS: Ninety infants with surgical NEC had a mean (±standard error) gestational age of 27.3 ± 0.4 weeks, birth weight 1008 ± 48 g, NEC onset at 25.2 ± 2.4 days, and resected bowel length of 29.2 ± 3.2 cm. Seventeen (18.9%) infants who had complete resection of the necrosed bowel had fewer (4; 23.5%) deaths and shorter lengths of hospital stay. In contrast, a group of 73 infants with some necrosis within the margins of resected bowel had significantly more (34; 46.6%) deaths and longer hospital stay. The combination of clinical and histopathological data gave better regression models for mortality and hospital stay. CONCLUSION: In surgical NEC, incomplete resection of necrotic bowel increased mortality and the duration of hospitalization. Regression models combining clinical and histopathological data were more accurate for mortality and the length of hospital stay. IMPACT: In infants with surgical NEC, complete resection of necrotic bowel reduced mortality and hospital stay. Regression models combining clinical and histopathological information were superior at predicting mortality and hospital stay than simpler models focusing on either of these two sets of data alone. Prediction of mortality improved with the combination of antenatal steroids, chorioamnionitis, and duration of post-operative ileus, with severity of inflammation and hemorrhages in resected intestine. Length of hospital stay was shorter in infants with higher gestational ages, but longer in those with greater depth of necrosis or needing prolonged parenteral nutrition or supervised feedings.

Lymphocytic Colitis With Increased Apoptosis: A Marker of Mutation in T-Cell-Mediated Immunity?

Lymphocytic colitis is a subtype of microscopic colitis that is mostly seen in adults. It presents mainly as chronic nonbloody diarrhea, with the hallmark of normal or near-normal endoscopy. In this case series, we are presenting 4 pediatric patients with lymphocytic colitis with prominent apoptosis of the colonic gland epithelium. Remarkably, all the patients have genetic mutations known to be associated with autoimmune enteropathy. Three patients have a CTLA4 mutation, and 1 patient has an STAT3 mutation. These mutations were previously reported in association with inflammatory bowel disease, but a specific connection with lymphocytic colitis has not been described. This report investigates the histopathology of such lesions in children and adolescents.

Chondroblastoma-like Osteosarcoma.

CONTEXT.­: Chondroblastoma-like osteosarcoma is an exceedingly rare variant of osteosarcoma, with 22 cases reported in the English-language literature. The tumor is slightly more common in males, with a broad age range (from childhood to elderly). The most commonly involved bones are the metatarsus and tibia, followed by the femur. Most tumors have malignant or worrisome radiographic findings. Prognosis is variable, depending on the presence or absence of lung metastases, local recurrence, and probably tumor location. Histologically, chondroblastoma-like osteosarcoma is characterized by monotonous, minimally to moderately atypical rounded cells with ovoid nuclei resembling chondroblastoma, and abnormal osteoid deposition with destruction of the bone. OBJECTIVE.­: To review the clinical, radiographic, and histopathologic features of chondroblastoma-like osteosarcoma. DATA SOURCES.­: PubMed-published chondroblastoma-like osteosarcoma cases in the English-language literature. CONCLUSIONS.­: Although exceedingly rare, chondroblastoma-like osteosarcoma should be considered in the differential diagnosis of chondroblastoma, especially in the presence of radiologic findings suggestive of an aggressive lesion.

Umbilical Cord Teratomas Associated With Congenital Malformations.

CONTEXT.­: Congenital mature teratomas of the umbilical cord are extremely rare and pose a challenge in prenatal diagnosis. Mature teratomas are defined as tumors composed of mature tissues derived from more than 1 germ cell layer. The tumor often shows solid and cystic components, which adds to the difficulty of prenatal diagnosis. Although benign, mature teratomas of the umbilical cord are commonly associated with congenital malformations of the fetus with variable severity and rarely, with chromosomal abnormalities. OBJECTIVE.­: To review the clinical, radiologic, gross, and histologic features of umbilical cord teratoma; its differential diagnosis; and to emphasize the increased risk of associated congenital malformations. DATA SOURCES.­: Umbilical cord teratoma cases published in the literature. CONCLUSIONS.­: Umbilical cord teratomas are difficult to diagnose by imaging studies alone and require histopathologic examination for diagnosis. Given the increased risk of associated anomalies and malformations, the finding of umbilical cord teratoma should trigger a detailed and comprehensive evaluation of the neonate for additional abnormalities.

Non-Helicobacter pylori Gastric Intestinal Metaplasia in Children: A Series of Cases and Review of the Literature.

In the pediatric population, Gastric Intestinal Metaplasia (GIM) is a finding with unknown frequency and, more importantly, unknown clinical implications. The relationship between Helicobacter pylori (HP) infection and GIM is well documented, as well as an association between duodenogastric reflux and GIM. We present two cases of pediatric patients with GIM along with a review of the literature. The diagnosis of GIM may have adverse clinical implications and should be made with caution in a child. The association of GIM and adenoma/dysplasia and carcinoma is rarely seen in children, primarily because the time required for these to develop takes the individual into adulthood. Treatment, long-term consequences, and surveillance protocols are not well established in the pediatric population. Studies to evaluate the long-term natural history, treatment, and surveillance protocols in children with GIM are needed.

Glomuvenous malformations in a young man.

A young man presented with blue nodules on the trunk, face, and extremities that gradually increased in number and size. His mother had similar lesions. Initially, blue rubber bleb nevus syndrome was suspected, but histological findings confirmed the diagnosis of hereditary glomuvenous malformations. Making the correct diagnosis spares the patient unnecessary evaluation for the arteriovenous malformations of the gastrointestinal tract associated with the former diagnosis.

Fibrolamellar hepatocellular carcinoma in ascitic fluid: A case report with cytohistological correlation.

The fibrolamellar variant of hepatocellular carcinoma (FL-HCC) is distinguished from other hepatocellular carcinoma's (HCC) by its unique clinical and pathological features. Cytological features of this tumor on fine needle aspiration have been described earlier. We report a rare case of a 17-year-old African American male with metastatic FL-HCC, diagnosed by body fluid cytology. The patient presented with ascites and computed tomography (CT) scan revealed multiple omental masses and liver lesions. The fluid sample was obtained along with the omental biopsy and was found positive for metastatic fibrolamellar hepatocellular carcinoma. The fluid cytology showed atypical polygonal cells with enlarged nuclei, prominent nucleoli, and abundant granular cytoplasm. Cytomorphologic features of FL-HCC presenting in body fluids have been rarely described before. This case enriches the cytopathology literature by providing awareness of this tumor presenting as metastasis in body fluids, especially in young individuals with liver lesions. Presence of a concurrent biopsy specimen provided cytohistological correlation, as it remains the gold standard for the accuracy and reliability of cytological diagnoses. Diagn. Cytopathol. 2016;44:757-760. © 2016 Wiley Periodicals, Inc.