Bartonella henselae infection-mediated shunt nephritis.

Serum anti-neutrophil cytoplasmic antibody (ANCA) positivity with membranoproliferative pattern on renal biopsy can be due to ANCA-associated vasculitis as well as chronic indolent infections. We present the case of an adolescent boy with congenital heart disease and history of cardiac surgery who presented with severe acute kidney injury requiring hemodialysis. Renal biopsy showed membranoproliferative glomerulonephritis with full-house immunofluorescence pattern. Low serum complements, PR3 ANCA positivity and elevated Bartonella immunoglobulin titers suggested a diagnosis of infective endocarditis-associated glomerulonephritis. Cardiac shunt revision and antibiotic therapy lead to improvement in kidney function. Chronic infections lead to formation of immune complexes that may cause deposit within the renal parenchyma and induce production of ANCA. The distinction of ANCA-associated vasculitis and chronic infections causing acute kidney injury is important in determining therapeutic management. While rare in the pediatric population, we highlight the importance in considering indolent infections in patients with acute glomerulonephritis and ANCA positivity, especially with risk factors.

Immunohistochemical Loss of DPC4 in Tumors With Mucinous Differentiation Arising in or Involving the Gynecologic Tract.

DPC4 immunohistochemistry (IHC) is usually part of the work-up of mucinous neoplasms in the ovary where the distinction between an ovarian primary and metastatic pancreaticobiliary adenocarcinoma (PanACa) must be made. Although DPC4 IHC is lost in about 55% (46%-61%) of PanACas and typically retained in most primary ovarian mucinous neoplasms, no study has evaluated the expression of this marker in a large cohort of neoplasms arising in or involving gynecologic (GYN) organs. In this study, we retrospectively analyzed the expression of DPC4 IHC in a total of 251 tumors and lesions related to the GYN tract in which DPC4 IHC stain was performed during the initial pathology evaluation. Of these, 138 were primary GYN tumors and lesions, 31 were metastatic GYN tumors involving non-GYN sites, and 83 were metastatic non-GYN tumors involving the GYN tract. We identified 27 cases with loss of DPC4 IHC expression of which 20 cases met the inclusion criteria (i.e. clinical information was available to determine the site of tumor origin). We observed that loss of DPC4 nuclear expression was most commonly seen in tumors of endocervical origin (n=7), of which 5 were gastric-type cervical adenocarcinomas (GCxACa) and 2 were usual-type cervical adenocarcinomas, either primary or metastatic. This was followed by tumors of the pancreaticobiliary tract (n=5), ovary (n=2), and appendix (n=1). In addition, 1 gastric-type vaginal adenocarcinoma (GVaACa) also showed loss of DPC4. Our findings indicate that in female patients with mucinous neoplasms involving the ovary or other sites, with loss of DPC4 by IHC, and negative pancreaticobiliary imaging, the possibility of an occult GCx/GVaACa, and rarely an ovarian primary must be considered.

IgG4-Related Appendiceal Disease: A First Case Report Fulfilling All Pathological Diagnostic Criteria and With Concomitant S100-Positive Dendritic/Schwann Cell Hyperplasia.

IgG4-related disease is a recent entity that has been described in a wide variety of organ systems. A 46-year-old female presented with acute appendicitis accompanied by a mass-forming lesion, raising a concern for neoplasm, and therefore, hemicolectomy was performed. The lesion revealed a dense lymphoplasmacytic infiltrate accompanied by storiform fibrosis and obliterative phlebitis. The IgG4/IgG plasma cell ratio was >50%, and the number of IgG4-positive plasma cells was >100/high-power field. In order to assess the IgG4/IgG plasma cell ratio, MUM1 was employed instead of IgG to successfully estimate the plasma cell concentration. There was also a concomitant hyperplasia of S100-positive cell, which could represent dendritic or Schwannian origin and possibly play a pathophysiologic role. The hyperplasia was significant by itself that it may mimic a mass-forming lesion. This newly described entity of the past decade deserves increased recognition due to clinical implication and surgical morbidity. This is the first case of IgG4-related disease in the appendix to our knowledge that fully satisfied all the pathological diagnostic criteria. We would like to also highlight our innovative approach of evaluating the IgG4/IgG plasma cell.

Epstein-Barr Virus-Positive CD20- and CD45-Negative Diffuse Large B-Cell Lymphoma: A Diagnostic Challenge.

Diffuse large B-cell lymphoma (DLBCL) is characterized by medium- to large-sized neoplastic cells that express a wide range of B-cell markers including CD19, CD20, CD22, and CD79a. Also, as this is a hematopoietic malignancy, there is expression of the leukocyte common antigen CD45. Lack of CD20 expression occurs in a specific rare heterogeneous subgroup of DLBCL including primary effusion lymphoma, plasmablastic lymphoma, ALK-positive large B-cell lymphoma, and large B-cell lymphoma arising in HHV8+ multicentric Castleman disease. In this article, we report a rare case of CD20- and CD45-negative Epstein-Barr virus-positive DLBCL in which the entities listed above were ruled out, thereby posing a significant diagnostic challenge. Arriving at the correct diagnosis of Epstein-Barr virus-positive DLBCL was supported by immunoreactivity for the B-cell transcription factor Oct-2 and the pan-B cell marker CD79a.

Salivary Gland Heterotopia in the Gastroesophageal Junction: A Case Series and Review of the Literature.

Heterotopia is defined as the presence of mature, histologically normal, tissue in unusual anatomic sites. When this heterotopic tissue forms a mass, it is called a choristoma. This case series describes 3 cases of gastroesophageal junction (GEJ) salivary heterotopias. While heterotopias are usually incidental findings, choristomas can clinically and endoscopically mimic carcinomas and might lead to unnecessary procedures for the patients. Clinicians should therefore be aware of this entity. Literature search, however, failed to show any reports of salivary gland heterotopias in the GEJ. In fact, literature review revealed only 6 reported cases of salivary gland choristoma in the gastrointestinal tract, none at the GEJ. In this case series, we report 2 cases of salivary gland heterotopia and one case of salivary gland choristoma arising at the GE junction. To our knowledge, this is the first series of its kind in the literature.

Primary Epidermoid Cyst of Biliary Duct Presenting as Choledochal Cyst.

Choledochal cyst is a cystic dilation of the biliary tree that can increase the risk of malignancy in bile ducts and the gallbladder. These are usually lined by bile duct epithelium, which may undergo intestinal and squamous metaplasia. This is the first report of clinically diagnosed type II choledochal cyst that is entirely lined by metaplastic stratified squamous epithelium, unlike most other cysts, which are histologically lined by bile duct epithelium. This observation can potentially explain the underlying pathogenic mechanism of rare reports of squamous cell carcinomas arising in bile duct systems.