Cystic rete testis in a central bearded dragon (Pogonavitticeps).

The rete testis forms from the mesonephric tubules in a series of interconnected channels in which spermatozoa travel in a high volume of fluid between the seminiferous tubules and efferent ductules. Cystic rete testis can be identified by uni- or multilocular cysts with a wall lined by low cuboidal epithelial cells and a dense fibrous stroma. An 11-year-old male central bearded dragon (Pogona vitticeps) was evaluated for a coelomic mass.

IgG4-related disease of the tubular gastrointestinal tract: A rare cause of lymphoplasmacytosis, eosinophilia, and mass-forming lesions.

IgG4-related disease (IgG4RD) is a systemic fibroinflammatory condition that can affect multiple organs, but rarely involves the tubular gastrointestinal (GI) tract. We identified patients with definitive or possible IgG4RD of the GI tract diagnosed at our institution. Our cohort included 8 patients with a median age of 37 years (range 15-73) and a slight male predominance (63 %).

Metastatic Intraparotid Balloon Cell Melanoma: A Diagnostic Challenge.

Background: BCM is an uncommon cytomorphologic variant with the potential to mimic unrelated neoplastic conditions, especially in the absence of a known cutaneous primary lesion or limited access to immunohistochemical stains.

Case Presentation: A 28-year-old male patient presented with recent onset parotid gland mass. The mass was excised, and the subsequent workup elicited an interpretation of metastatic balloon cell melanoma (BCM).

A Comprehensive Review of Kimura Disease.

Purpose: Kimura disease (KD) is a rare, chronic inflammatory disorder that primarily affects the head and neck regions, often mimicking neoplastic conditions. This study aims to provide a comprehensive review of KD, focusing on its clinical presentation, diagnostic challenges, optimal management strategies, and primary histopathologic differential diagnosis.

Methods: A systematic review of literature was conducted using PubMed, Scopus, and Google Scholar databases.

Lethal, disseminated infection with an oomycete () in captive, deep-sea isopods ( and ) in California.

There are no previous publications on diseases of Japanese isopods () or giant deep-sea isopods (). is a pathogenic oomycete that infects external tissues of abalone, mantis shrimp, and European lobsters, and has not been previously reported in isopods. The purpose of this study is to describe the clinical presentation, gross findings, and histologic lesions caused by in and kept in a public aquarium in California.

The International System for Reporting Serous Fluid Cytopathology survey data reveal substantial variability in the reporting and utilization of pelvic washing and peritoneal fluid specimens among pathologists and gynecologic oncologists.

Introduction: Pelvic and peritoneal washings (PW) are often taken during gynecologic resections when the presence of a neoplastic process is known or suspected. A positive PW may upstage a patient and/or impact a patient's prognosis and treatment. Two surveys were created to inform The International System for Serous Fluid Cytology, a standardized reporting system, regarding the practice and utilization of PW cytology.

Chimeric antigen receptor (CAR) T-cell therapy-related gastrointestinal toxicity: Histologic features and morphologic mimics.

Chimeric antigen receptor (CAR) T-cell therapy is a contemporary treatment modality for hematologic malignancies, with potential future applications in solid tumors. While the clinical side effects of CAR T-cell therapy are well-documented, histologic correlations of gastrointestinal (GI) toxicity remain underreported. This study prospectively identified 5 sets of GI biopsies from 3 patients presenting with CAR T-cell therapy-associated GI toxicity.

Renal Cell Carcinoma in a Common Marmoset: First Report and a Brief Review of Nonhuman Primate Literature.

Renal cell carcinoma (RCC) is a malignant form of urogenital cancer that arises from renal tubular epithelial cells. Here, we describe a case of renal cell carcinoma in a common marmoset (Callithrix jacchus). Immunohistochemistry demonstrated positive reactivity for PAX8 and CD10 in the renal neoplasm.

Human Papillomavirus Testing in Head and Neck Carcinomas: Guideline Update.

Context.—: In 2018, an evidence-based guideline was published by the College of American Pathologists to develop recommendations for the testing, application, interpretation, and reporting of high-risk human papillomavirus and surrogate marker tests in head and neck carcinomas. Substantial new evidence has prompted a review, including data on human papillomavirus (HPV) in nonoropharyngeal anatomic sites, HPV global rates, p16 immunohistochemistry, and HPV testing performance in cytology specimens, and performance of p16 immunohistochemistry as a surrogate marker.

Nerve Sheath Tumor in a Cynomolgus Macaque (Macaca fascicularis) and Diagnostic Differentiation from Amelanotic Melanoma.

There are few reports describing spontaneous neoplasms in cynomolgus macaques, despite the frequent use of this species in laboratory research. This report describes cytologic, histologic, and immunohistochemical findings of a cutaneous to subcutaneous nerve sheath tumor located within the haired skin of the abdomen of a 2.5-y-old, intact, female, captive Mauritius cynomolgus macaque.

Prevalence of osteosarcoma and investigation of risk factors in military working dogs: a retrospective study using data from the Deceased Military Working Dog Database.

A retrospective study of military working dogs (MWDs) that were on active duty within the Department of Defense from 2000 to 2023 was conducted for the prevalence of osteosarcoma (OSA), histological subtypes and metastatic potential, and to examine potential risk factors. The prevalence of OSA in privately owned dogs (ie, pets of Department of Defense beneficiaries) that were patients of veterinary treatment facilities from 2000 to 2023 was used as a control. Between 2000 and 2023, 2,220 deceased MWD records had pathology data available for review, 27 of which had OSA (1.

Langerhans Cell Histiocytosis and Other Histiocytic Lesions.

Background: Histiocytoses, including Langerhans cell histiocytosis (LCH), comprise a diverse group of histiocytic disorders characterized by the abnormal accumulation and proliferation of histiocytes in various tissues or organs throughout the body, ranging from benign, self-limited conditions to aggressive malignancies and systemic inflammatory syndromes. These lesions present unique diagnostic challenges due to their broad spectrum of clinical presentations, overlapping histopathological and immunophenotypical features, and genetic complexity.

Methods: This review analyzes major histiocytic lesions, focusing on their epidemiology, clinical presentations, histologic and immunophenotypic features, and genetic characteristics to facilitate accurate diagnosis and differentiation among these histiocytoses.

Eosinophils and the Head and Neck.

Tissue eosinophilia is a common finding during histopathologic evaluation and recognizing its presence oftentimes aids pathologists in arriving at the correct diagnosis. The head and neck region is an anatomic location where an abundance of eosinophil-rich disorders occur. In this review, we seek to provide an overview of eosinophil morphology, production, regulation, lifecycle, recruitment, function, and mediators.

Dermatologic Lesions with Eosinophilia in the Head and Neck.

Background: Dermatologic lesions with notable eosinophilic infiltration of the head and neck region represent a diverse group of conditions, ranging from benign to malignant proliferations.

Methods: We performed a comprehensive literature review focusing on head and neck dermatologic conditions that commonly present with a prominent eosinophilic infiltrate.

Results: This review provides an overview of common entities showing prominent associated eosinophilic inflammatory infiltrates in this region, including epithelioid hemangioma, eosinophilic cellulitis (Wells syndrome), eosinophilic folliculitis, eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome), granuloma faciale, and Langerhans cell histiocytosis (LCH).

Viral and squamous papillomas in captive polar bears ().

Papillomas, many of which are virally induced, are common proliferative cutaneous and mucocutaneous lesions in multiple species, exhibiting characteristic histologic cytopathic changes that distinguish them from nonviral squamous papillomas. A single case report of a novel papillomavirus, Ursus maritimus papillomavirus-type 1, in a polar bear has been reported without investigation into any association between this virus and papilloma formation. We identified papillomas in 3 polar bears.

Transcription of hepatitis B surface antigen shifts from cccDNA to integrated HBV DNA during treatment.

The cornerstone of functional cure for chronic hepatitis B (CHB) is hepatitis B surface antigen (HBsAg) loss from blood. HBsAg is encoded by covalently closed circular DNA (cccDNA) and HBV DNA integrated into the host genome (iDNA). Nucleos(t)ide analogs (NUCs), the mainstay of CHB treatment, rarely lead to HBsAg loss, which we hypothesized was due to continued iDNA transcription despite decreased cccDNA transcription.

Colorectal adenosquamous carcinoma: clinicopathologic analysis of two large cohorts and literature review confirm poor prognosis and reveal prognostic aspects.

Aims: We compiled two cohorts of colorectal adenosquamous carcinoma (ASC) to describe its histologic and molecular aspects using modern parameters to compare them with literature reports using meta-analysis of cohorts and individual case series.

Methods And Results: We identified 53 colorectal ASC from 19 North American academic medical centres, in addition to national database reports on 94 Dutch cases. We analysed available clinical, histologic, and immunohistochemical features and patient outcome.

Head and Neck Classic Hodgkin, T and NK Lymphomas with Eosinophilia.

Eosinophilia is a notable feature in various hematological malignancies, including specific types of leukemias and lymphomas that may occur in the head and neck. In hematologic malignancies, eosinophilia can be primary, driven by genetic abnormalities, or secondary, resulting from cytokine and chemokine production by the neoplastic cells or the tumor microenvironment. This review examines the association between eosinophilia and head and neck hematolymphoid malignancies including Classic Hodgkin lymphoma, T-cell lymphoblastic leukemia, mature T and NK-cell lymphomas, and Langerhans cell histiocytosis.

A novel viral infection in a Captive Colony of pelagic red crabs (Pleuroncodes planipes) from California.

Captive, pelagic red crabs (Pleuroncodes planipes) had shortened lifespans and cutaneous black spots. Histologically, epidermal and mesenchymal cells had 3-5 µm diameter intranuclear inclusions, necrosis, vacuolation, and/or hyperplasia. The remaining organs were histologically unremarkable.

HIV, measles, and syphilis: histopathologic characteristics of lymphatic system involvement of three reemerging infectious diseases.

The resurgence of measles, syphilis, and HIV presents a significant threat to global health, especially in the wake of the COVID-19 pandemic. These three infections involve lymph nodes and have unique pathologic findings in lymph nodes. We explore the pathological and clinical characteristics of these infections, focusing on their involvement of lymph nodes and their pathologic diagnosis in lymph node specimens.

Polyglucosan storage disease in a black-capped parrot (Pionitesmelanocephalus).

Following an episode of sudden lethargy, an 18-month-old female black-capped parrot (Pionites melanocephalus) died while being examined. On gross examination, there was fluid within the coelom, hepatomegaly with yellow colouration and the heart appeared enlarged with pallor throughout the myocardium. On histological examination, cardiomyocytes were swollen with loss of cross striations and contained 6-12-μm diameter intrasarcoplasmic pale grey inclusions of storage material.

Thirty years of surveillance of depleted uranium-exposed Gulf War veterans demonstrate continued effects to bone health.

During the spring of 2024, 33 members of a group of Gulf War I veterans wounded in depleted uranium (DU) friendly-fire incidents were seen at the Baltimore VA Medical Center for surveillance related to their combat exposure. The cohort was assessed with a protocol which includes exposure monitoring for total and isotopic uranium (U) concentrations in urine and a comprehensive assessment of health outcomes including measures of bone metabolism and bone mineral density (BMD). An audiometry examination of the cohort was added to assess for acoustic trauma and toxic metal effects in this surveillance episode marking over 30 years since this exposure event.