Sclerosing mucoepidermoid carcinoma of salivary glands.

Sclerosing mucoepidermoid carcinoma (SMEC) of the salivary glands is a rare variant of low-grade mucoepidermoid carcinoma with scanty cellular atypia characterized by marked fibrosis/sclerosis and a rich inflammatory infiltrate. Herein, we report 25 unpublished cases of SMEC, two of them with prominent eosinophilia (2/25; 8%) and three with abundant IgG4-positive plasma cells (3/25; 12%). In our series of salivary SMEC, molecular analysis using fluorescence in situ hybridization (FISH) and/or next-generation sequencing (NGS) provided evidence of MAML2 gene rearrangement in 18 cases of the 21 analyzable cases tested (86%), while this gene locus was intact in 3 cases (14%).

A diagnostic algorithm for sinonasal papillary non-keratinizing squamous cell carcinoma with DEK::AFF2 fusion and mimickers.

Sinonasal carcinomas represent a rare and diverse group of tumors, presenting diagnostic complexities due to their varied histological and molecular features. To ensure accurate differentiation among these malignancies, a systematic and stepwise approach is paramount. Even with the morphological similarities between poorly differentiated (non) keratinizing sinonasal squamous cell carcinoma (SNSCC) and DEK::AFF2 SNSCC, the two lesions are distinguishable using the surrogate immunohistochemical marker AFF2 or molecular testing for DEK::AFF2 mutation.

Intraparotid Ganglioneuroma: A rare case report.

Ganglioneuromas (GNs) are slow-growing, benign tumors arising from Schwann cells, gangliocytes, and neuronal tissues. We report a rare intraparotid ganglioneuroma in a 42-year-old female presented with a parotid mass. The onset of the lesion dated back to 2021, but the growth was remarkable only in November 2022.

Rearrangement of Characterizes a Subset of Pediatric Parotid Mucoepidermoid Carcinomas Arising Metachronous to Acute Lymphoblastic Leukemia.

Metachronous mucoepidermoid carcinomas (MMEC) may occur in association with childhood leukemias and lymphomas. We compared molecular abnormalities of MMEC in patients with ALL with the abnormalities found in primary mucoepidermoid carcinomas (MECs) in pediatric cases and young adults. Immunohistochemical stains for p63 and SOX10, molecular alterations in and genes detected by FISH and/or next-generation sequencing were studied in 12 pediatric MMECs secondary to ALL and six primary MECs in pediatric patients and young adults.