YAP1::KMT2A-rearranged sarcomas harbor a unique methylation profile and are distinct from sclerosing epithelioid fibrosarcoma and low-grade fibromyxoid sarcoma.

Sclerosing epithelioid fibrosarcoma (SEF) was originally described as a peculiar variant of fibrosarcoma in 1995. Subsequent studies showed that conventional SEF was associated with both immunohistochemical expression of MUC4 and EWSR1/FUS gene rearrangements with CREB3L1 as the predominant fusion partner. Since then, a distinct group of fibrous tumors characterized by YAP1::KMT2A and KMT2A::YAP1 gene rearrangements and SEF-like morphology has been described.

Reappraisal of soft tissue myoepithelial tumors by DNA methylation profiling reveals an epigenetically distinct group of mostly fusion-driven neoplasms.

Soft tissue myoepithelial tumors (METs) are diagnostically challenging tumors that require careful histologic and immunohistochemical characterization for accurate classification. Nearly half of METs show recurrent EWSR1 or FUS gene rearrangements with a diverse set of fusion partners. The diversity of fusion partners and lack of known driver abnormalities in many cases raises the question of whether METs represent a uniformly distinct tumor entity.

TFE3-rearranged Head and Neck Neoplasms: Twenty-two Cases Spanning the Morphologic Continuum Between Alveolar Soft Part Sarcoma and PEComa and Highlighting Genotypic Diversity.

TFE3 rearrangements characterize histogenetically, topographically, and biologically diverse neoplasms. Besides being a universal defining feature in alveolar soft part sarcoma (ASPS) and clear cell stromal tumor of the lung, TFE3 fusions have been reported in subsets of renal cell carcinoma, perivascular epithelioid cell tumor (PEComa), epithelioid hemangioendothelioma and ossifying fibromyxoid tumors. TFE3-related neoplasms are rare in the head and neck and may pose diagnostic challenges.

Xanthogranulomatous epithelial tumors/keratin-positive giant cell-rich tumors involving the head and neck: report of seven cases and review of the literature.

Xanthogranulomatous epithelial tumor (XGET) and HMGA2::NCOR2 fusion keratin-positive giant cell-rich tumor (KPGCT) are recently described morphologically overlapping rare neoplastic entities characterized by HMGA2::NCOR2 fusions, low-grade biological behavior, and a strong predilection for young females. To date, 47 cases have been reported with only four occurring in head and neck anatomic locations. In this study, we describe the clinicopathologic, immunohistochemical, and molecular findings of seven XGET/KPGCTs occurring in the head and neck region.

Assessing Morphological Diversity of Acinic Cell Carcinoma of Salivary Glands at a Tertiary Care Hospital in Pakistan.

Introduction: Acinic cell carcinoma (AciCC) is a rare clinical entity and a salivary gland malignancy. It is associated with wide histological variations in the cytomorphological patterns.

Methods: Sixty cases diagnosed as AciCC from 2002 to 2023 were assessed for diverse cytomorphological patterns.

A Comprehensive Clinicopathologic and Molecular Reappraisal of GLI1 -altered Mesenchymal Tumors with Pooled Outcome Analysis Showing Poor Survival in GLI1 - amplified Versus GLI1- rearranged Tumors.

GLI1 -altered mesenchymal tumor is a recently described distinct pathologic entity with an established risk of malignancy, being defined molecularly by either GLI1 gene fusions or amplifications. The clinicopathologic overlap of tumors driven by the 2 seemingly distinct mechanisms of GLI1 activation is still emerging. Herein, we report the largest series of molecularly confirmed GLI1 -altered mesenchymal neoplasms to date, including 23 GLI1- amplified and 15 GLI1 -rearranged new cases, and perform a comparative clinicopathologic, genomic, and survival investigation.

Role of SOX10 Immunohistochemical Expression in Diagnosing Triple Negative Breast Cancer and Its Correlation With Clinicopathological Features.

Background: Triple-negative breast cancer (TNBC) poses a diagnostic challenge for histopathologists due to the reduced frequency of breast-specific markers. SOX10 has emerged as a useful diagnostic marker for TNBC. The aim of our study was to determine the frequency of SOX-10 immunohistochemical (IHC) expression in our cohort and assess its correlation with clinicopathological and histological features.

Myoepithelial tumors of soft tissue and bone in children and young adults: A clinicopathologic study of 40 cases occurring in patients ≤ 21 Years of age.

Myoepithelial tumors of the soft tissue and bone occurring in patients 21 years of age and younger are rare, and their clinicopathologic features remain incompletely understood. We studied a well-characterized series of 40 such tumors. Cases were retrieved from our archives for the period 2009-2022 and re-reviewed.

Recurrent Wnt Pathway and ARID1A Alterations in Sinonasal Olfactory Carcinoma.

Sinonasal tumors with neuroepithelial differentiation, defined by neuroectodermal elements reminiscent of olfactory neuroblastoma (ONB) and epithelial features such as keratin expression or gland formation, are a diagnostically challenging group that has never been formally included in sinonasal tumor classifications. Recently, we documented that most of these neuroepithelial neoplasms have distinctive histologic and immunohistochemical findings and proposed the term "olfactory carcinoma" to describe these tumors. However, the molecular characteristics of olfactory carcinoma have not yet been evaluated.

EWSR1::POU2AF3(COLCA2) Sarcoma: An Aggressive, Polyphenotypic Sarcoma With a Head and Neck Predilection.

EWSR1::POU2AF3 (COLCA2) sarcomas are a recently identified group of undifferentiated round/spindle cell neoplasms with a predilection for the head and neck region. Herein, we report our experience with 8 cases, occurring in 5 men and 3 women (age range, 37-74 years; median, 60 years). Tumors involved the head/neck (4 cases), and one each the thigh, thoracic wall, fibula, and lung.

Solitary fibrous tumor of head and neck region; A clinicopathological study of 67 cases emphasizing the diversity of histological features and utility of various risk stratification models.

Background: Head and neck SFT (HNSFT) exhibit diverse histological features and can mimic various neoplasms with different treatment and behavior. While risk stratification systems have been developed for this tumor at various anatomic sites, a specific scheme for head and neck tumors is lacking. Our aim was to describe the histologic patterns present in HNSFT cases as well as assess the utility of risk assessment models in this location.

Clinicopathological features of dysembryoplastic neuroepithelial tumor: a case series.

Background: Dysembryoplastic neuroepithelial tumors are rare benign supratentotrial epilepsy-associated glioneuronal tumors of children and young adults. Patients have a long history of seizures. Proper surgical resection achieves long term seizure control.

Renal neuroendocrine tumors: clinical and molecular pathology with an emphasis on frequent association with ectopic Cushing syndrome.

Renal neuroendocrine tumors (RenNETs) are rare malignancies with largely unknown biology, hormone expression, and genetic abnormalities. This study aims to improve our understanding of the RenNETs with emphasis of functional, hormonal, and genetic features. Surgically resected RenNETs (N = 13) were retrieved, and immunohistochemistry and next-generation sequencing (NGS) were performed in all cases.

"PRRX1-rearranged mesenchymal tumors": expanding the immunohistochemical profile and molecular spectrum of a recently described entity with the proposed revision of nomenclature.

Since the publication of the 2020 World Health Organization classification of soft tissue and bone tumors, the classification of "fibroblastic" tumors has expanded to include a novel subset of tumors characterized by PRRX1::NCOA1/2 gene fusions. These tumors defy conventional classification and are morphologically distinct, characterized by a multi-nodular growth of bland spindle cells suspended in a myxo-collagenous stroma with mild cytologic atypia, "staghorn-like" vessels, and variable perivascular hyalinization. Mitotic activity is rare, and necrosis is not identified.

Hybrid odontogenic lesions: A case series of a rare entity.

Background: The occurrence of hybrid odontogenic lesions with two or more morphologically distinct components is a rare phenomenon and poses a diagnostic challenge. We aimed to study the clinical, radiological, and pathological features and behavior of hybrid odontogenic lesions, to enhance awareness about these rare lesions.

Method: Hematoxylin and Eosin slides of hybrid odontogenic lesions diagnosed between January 01, 2012 and December 31, 2020, were reviewed.

Hydatid disease of central nervous system, a clinicopathological study of 33 cases.

Objectives: Involvement of central nervous system (CNS) by Hydatid cyst is rare comprising 0.5-4% of all hydatid cysts and principally affecting those younger than 20 years, giving rise to cystic masses mostly in the cerebral hemispheres. To report the clinicopathological findings of CNS hydatid cysts, we diagnosed and review the findings of the previous studies.

Chondroblastoma of foot bones; a clinicopathological study of 29 cases confirming the diagnostic utility of H3K36M and H3G34W antibodies at an uncommon site.

Objective: Chondroblastoma (CB) is a benign cartilaginous bone neoplasm which commonly occurs in long bones of adolescents. CB can uncommonly involve foot. Its mimics include both benign and malignant lesions.

Automated Battery Making Fault Classification Using Over-Sampled Image Data CNN Features.

Due to the tremendous expectations placed on batteries to produce a reliable and secure product, fault detection has become a critical part of the manufacturing process. Manually, it takes much labor and effort to test each battery individually for manufacturing faults including burning, welding that is too high, missing welds, shifting, welding holes, and so forth. Additionally, manual battery fault detection takes too much time and is extremely expensive.

Events in CNS Tumor Pathology Post-2016 WHO CNS: cIMPACT-NOW Updates and Other Advancements: A Comprehensive Review Plus a Summary of the Salient Features of 2021 WHO CNS 5.

Introduction: The 2016 World Health Organization Classification (WHO) of Tumors of the Central Nervous System (CNS) represented a major change. It recommended an "integrated diagnosis" comprising histologic and molecular information facilitating a more precise diagnosis of specific CNS tumors. Its goal was to provide greater diagnostic precision and reproducibility resulting in more clinical relevance and predictive value, ultimately leading to better patient care.

Anaplastic Large-cell Lymphoma Involving Gastrointestinal Tract: A Clinicopathologic Study of 25 Cases of a Rare Tumor at a Rare Site.

Anaplastic large-cell lymphoma (ALCL) is an uncommon lymphoma divided into anaplastic lymphoma kinase (ALK) positive, ALK negative, and breast implant-associated (BIA) ALCL. Gastrointestinal tract involvement is very rare and may be difficult to diagnose. Its recognition is crucial as prognostic ramifications are different.

TFG::MET-rearranged soft tissue tumor: A rare infantile neoplasm with a distinct low-grade triphasic morphology.

This article presents 2 cases of TFG::MET-rearranged mesenchymal tumor, an extremely rare molecular subset among an emerging group of mesenchymal neoplasms with kinase gene (NTRK, BRAF, RET and others) alterations. Both tumors were congenital, occurred in female patients and presented as huge masses on the trunk and thigh, measuring 18 and 20 cm in the largest dimension. Both cases showed identical areas with a distinctive triphasic morphology resembling fibrous hamartoma of infancy (FHI), consisting of haphazardly arranged ovoid to spindled cells traversed by variably cellular and hyalinized fascicles admixed with (most likely non-neoplastic) adipose tissue.