New Insights into Tumor Heterogeneity: A Case of Solid-Oncocytic Epithelial-Myoepithelial Carcinoma of the Parotid Gland Harboring a HRAS and Heterogeneous Terminating ARID1A Mutation.

ABSTRACT: Epithelial-myoepithelial carcinoma (EMC) can be a challenging diagnosis due to a lack of obvious invasion and bland cytology. We report an unusual case of a low-grade EMC with prominent fibrous stroma, an extensive solid-oncocytic differentiation and limited areas of morphological clearly identifiable characteristic biphasic (tubular) differentiation, clear cells and PAS-positive secretions/calcifications. Both areas were investigated by next generation sequencing (Oncomine comprehensive assay) and revealed a typical concordant HRAS p.Q61R mutation. An additional heterogeneous ARID1A (p.E672*) terminating mutation with loss of heterozygosity, which could be visualized predominantly in the solid-oncocytic differentiation by immunohistochemical loss of ARID1A protein expression, was found. T

SUBMITTER: Rupp NJ 

PROVIDER: S-EPMC7235098 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature