Clinicopathologic Features of a Rare and Underrecognized Variant of Early-stage Primary Biliary Cholangitis With Ductopenia.

Primary biliary cholangitis (PBC) with early cholestasis and extensive bile duct loss but no significant fibrosis or cirrhosis is rare and underrecognized. We aimed to clarify the clinicopathology features and prognosis of these variants of patients with early-stage PBC with ductopenia. From January 2009 to January 2023, we retrospectively collected the laboratory and pathologic data of patients with early-stage PBC and recorded their liver-related events with a median follow-up of 4.

Immature PIT1-lineage Pituitary Neuroendocrine Tumors/Adenomas, a Morphologically Unique Pituitary Neuroendocrine Tumors/Adenomas Commonly With Cytologic Atypia Features and a Predilection for Aggressive Clinical Potential.

Immature PIT1-lineage pituitary neuroendocrine tumors (PitNETs)/adenomas (Immature PIT1-lineage tumors) are a rare and underrecognized subtype of PitNETs that exhibits distinct cytologic atypia features and aggressive clinical potential. This study characterizes the clinical, radiological, histologic, and immunohistochemical features of 15 immature PIT1-lineage tumors identified from 1084 PitNETs patients over 5 years. Our cohort of 6 males and 9 females had a median age of 37.

Claudin-18 and Mutation Surrogate Immunohistochemistry in Gastric-type Endocervical Lesions and their Differential Diagnoses.

Gastric-type endocervical adenocarcinomas (GAS) are aggressive HPV-independent neoplasms with molecular alterations in TP53 , STK11 , CDKN2A, and SMAD4 . Claudin-18 (CLDN18) has emerged as a useful marker to distinguish GAS from HPV-associated neoplasia. Its role in separating GAS from benign proliferations and exuberant endocervical glands is unknown.

Interpretation of p16 and p53 in the Classification of Squamous Cell Carcinoma of the Vulva-An Interobserver Agreement Study.

Squamous cell carcinoma of the vulva (vSCC) is currently categorized either as human papillomavirus (HPV) associated or independent. Immunohistochemical stains, p16INK4a (p16) and p53 are helpful biomarkers to support the designation of vSCC into 1 of the 3 tumor pathways: (1) HPV-associated, (2) HPV-independent, TP53 mutant, or (3) HPV-independent, TP53 wild type. Recently, a framework of p53 expression patterns in vSCC was proposed.

Clinicopathologic Features of Breast Tumors in Germline TP53 Variant-Associated Li-Fraumeni Syndrome.

We present one of the largest cohorts of TP53-pathogenic germline variants (PGVs) associated with patients with Li-Fraumeni syndrome (n = 82) with breast tumors (19 to 76 y; median age: 35). Most had missense variants (77%), followed by large gene rearrangements (LGRs; 12%), truncating (6%), and splice-site (5%) variants. Twenty-one unique germline missense variants were found, with hotspots at codons 175, 181, 245, 248, 273, 334, and 337.

The Spectrum of B-cell and Plasma Cell Proliferations in Nodal T Follicular Helper Cell Lymphomas.

B-cell and plasma cell proliferations are frequently observed in nodal T follicular helper (nTfh) cell lymphomas and can present a diagnostic challenge. These proliferations can be monotypic or monoclonal and morphologically resemble lymphoma or plasmacytoma, but their clinical behavior is poorly defined. In this study, we reviewed 414 cases of nTfh lymphoma seen over the past decade at our institution.

Sarcoid Vasculitis in the Skin: A Clinicopathologic Study of 8 Cases With Various Skin Lesions but the Common Unique Cannonball-like Vessel Destruction by Sarcoid Granulomas.

While the skin is a common target organ for sarcoidosis, cutaneous granulomatous vasculitis is rare among patients with sarcoidosis. Due to the lack of detailed studies on cutaneous sarcoid vasculitis, both dermatologists and pathologists remain unfamiliar with this rare but important vasculitic disorder. We clinicopathologically evaluated eight cases with biopsy-proven cutaneous vasculitis and cutaneous sarcoidosis and analyzed morphologic changes in the process of vasculitis for both small vessels and muscular vessels in detail.

IRF8 Demonstrates Positivity in a Significant Subset of Histiocytic and Dendritic Cell Neoplasms.

Histiocytic and dendritic cell neoplasms, especially histiocytic sarcoma, can show morphologic and phenotypic overlap with immature monocytic neoplasms. IRF8 immunohistochemical staining has been demonstrated to be useful in identifying monoblasts, but it has not been extensively studied in histiocytic and dendritic cell neoplasms. IRF8 immunohistochemistry was performed on cases of histiocytic sarcoma (HS, n=6), Langerhans cell histiocytosis (LCH, n=25), Rosai Dorfman disease (RDD, n=17), follicular dendritic cell sarcoma (FDCS, n=3), and Erdheim Chester disease (ECD, n=5), along with a control group that included a subset of myeloid neoplasms with monocytic differentiation.

Reappraisal of Oncocytic Adenocarcinoma: Unveiling Its Connection to Oncocytic Variants of Salivary Duct Carcinoma and Mucoepidermoid Carcinoma Through ImmunoHisto-Molecular Perspectives.

Oncocytic adenocarcinoma (OC) of the salivary glands is a rare and controversial entity. It was recently reclassified as "salivary carcinoma NOS and emerging entities" in the 2022 WHO classification of head and neck tumors. The lack of specific molecular alterations and its potential affiliation with other salivary gland carcinomas, such as the oncocytic mucoepidermoid carcinomas (OMEC) or the oncocytic subtype of salivary duct carcinomas (OSDC) justified this reclassification.

Sialadenopapillary Ductal Tumors: Unifying the Spectrum of Sialadenoma Papilliferum-like Tumors With Low Malignant Potential.

Sialadenoma papilliferum is a tumor characterized by surface papillary projections and glandular/microcystic proliferation at the lesion base. Cases in which surface involvement is absent have been termed "sialadenoma papilliferum-like intraductal papillary tumor." Similar tumors that are present in the mandible have been termed "tubulopapillary hidradenoma-like tumor of the mandible.

International Multicenter Retrospective Study From the Ultra-rare Sarcoma Working Group on Low-grade Fibromyxoid Sarcoma, Sclerosing Epithelioid Fibrosarcoma, and Hybrid Forms: Outcome of Primary Localized Disease.

The aim of the study was to report the outcome of primary localized low-grade fibromyxoid sarcoma (LGFMS), sclerosing epithelioid fibrosarcoma (SEF), and hybrid LGFMS/SEF (H-LGFMS/SEF). Patients with primary localized LGFMS, SEF, or H-LGFMS/SEF, surgically treated with curative intent from January 2000 to September 2022, were enrolled from 14 countries and 27 institutions. Pathologic inclusion criteria were predefined by expert pathologists.

Expanding the Spectrum of GLI1-rearranged Neoplasms of the Gastrointestinal Tract to Include Monophasic Keratin-positive Epithelial Neoplasms.

GLI1-altered tumors form a diverse group occurring in various anatomic locations. In the alimentary tract, the most established are gastroblastoma, a biphasic epithelial-mesenchymal neoplasm of the stomach, and plexiform fibromyxoma, a pure spindle cell neoplasm. The spectrum of GLI1-rearranged gastrointestinal tumors has recently expanded with reports of cases in other parts of the GI tract, some exhibiting gastroblastoma-like features and others being pure mesenchymal neoplasms.

Clear Cell Adenocarcinoma of the Urinary Tract Primary to the Renal Pelvis: A Multi-institutional Clinicopathologic and Molecular Study of Five Patients.

Clear cell adenocarcinoma (CCA) of the urinary tract is a rare malignancy and tumors involving the renal pelvis are notably sparse in the literature, with only 5 other patients reported. We present 5 patients, 4 women, and 1 man, with CCA of the renal pelvis. The age at presentation ranged from 29 to 81 years.

Are Ameloblastic Fibroma-related Lesions True Tumors?: Evidence Through CNA and BRAF Mutation Analysis.

Ameloblastic fibroma (AF) and related lesions, namely ameloblastic fibrodentinoma (AFD) and ameloblastic fibro-odontoma (AFO), span a spectrum from true neoplasms to hamartomas. The 2017 World Health Organization classification proposes that AFD and AFO are precursors to odontomas, yet their precise nature remains uncertain. This study examined 19 AF cases, 4 AFD, 15 AFO, 19 odontomas (OD, 14 complex, 5 compound), and 2 ameloblastic fibrosarcomas (AFS), focusing on clinical characteristics, recurrence, and molecular profiles.

Large-cell Basaloid Adenocarcinoma of the Lung: A Clinicopathologic Study of 12 Cases of a Distinctive Form of Lung Cancer Often Mistaken for Large-cell Neuroendocrine Carcinoma.

A distinctive form of lung adenocarcinoma that closely mimics large-cell neuroendocrine carcinoma is described. The tumors arose in 6 women and 6 men aged 46-86 years (mean=58.4).