Reevaluation of MAML2 fusion-Vnegative mucoepidermoid carcinoma: a subgroup being actually hyalinizing clear cell carcinoma of the salivary gland with EWSR1 translocation
Journal
Human Pathology
Journal Volume
61
Pages
9-18
Date Issued
2017
Author(s)
Abstract
Hyalinizing clear cell carcinoma (HCCC) is a rare salivary gland tumor with a specific EWSR1-ATF1 fusion gene and can have mucin production. Mucoepidermoid carcinoma (MEC) with a clear cell component is its morphologic mimic. Using MAML2 fluorescence in situ hybridization (FISH), a total of 49 MEC cases were separated into MAML2 fusion–positive (32 cases) and MAML2 fusion–negative groups (17 cases). This study used EWSR1 FISH to investigate MAML2 fusion–negative cases to identify previously unrecognized HCCC. Among 17 MAML2 fusion–negative cases, 3 had rearrangement of the EWSR1 gene and were reclassified as HCCC. Including 5 previously diagnosed HCCC cases, these 8 HCCC cases had a male-to-female ratio of 1:7, and most (7/8) tumors arose from oral minor salivary glands in the oral cavity (tongue base and palate). EWSR1-ATF1 fusion was confirmed by FISH in all 8 HCCC cases. The histologic features between genetically confirmed HCCC and MEC were compared. HCCC was significantly associated with minor salivary gland involvement, a discrepancy between low-grade cytology and intermediate- to high-grade histology using the MEC grading system, and absence of both epidermoid cells with abundant cytoplasm and goblet cells lining cysts or forming clusters. Clear cells and a hyalinized stroma were not specific for HCCC. HCCC may be erroneously classified as MEC because clear cells may be a minor histologic component and mucin production is not uncommon. Previously diagnosed MEC cases should be reevaluated, especially those arising from minor salivary glands or without MAML2 fusion. Careful histologic evaluation with supporting molecular testing can facilitate pathologic diagnoses. ? 2016 Elsevier Inc.
Other Subjects
mucin; DNA binding protein; EWSR1-ATF1 fusion protein, human; hyalin; MAML2 protein, human; nuclear protein; oncoprotein; transcription factor; tumor marker; adenosquamous carcinoma; adult; aged; Article; clear cell carcinoma; clinical article; cytoplasm; evaluation study; EWSR1 ATF1 fusion gene; EWSR1 gene; female; fluorescence in situ hybridization; fusion gene; gene rearrangement; gene translocation; goblet cell; histopathology; human; human tissue; hyalinizing clear cell carcinoma; immunohistochemistry; male; MAML2 gene; middle aged; oncogene; palate; salivary gland carcinoma; tongue; adolescent; cancer grading; chemistry; child; classification; gene fusion; genetic predisposition; genetics; mucoepidermoid tumor; pathology; phenotype; predictive value; salivary gland tumor; young adult; Adolescent; Adult; Aged; Biomarkers, Tumor; Carcinoma, Mucoepidermoid; Child; DNA-Binding Proteins; Female; Gene Fusion; Genetic Predisposition to Disease; Humans; Hyalin; Immunohistochemistry; In Situ Hybridization, Fluorescence; Male; Middle Aged; Neoplasm Grading; Nuclear Proteins; Oncogene Proteins, Fusion; Phenotype; Predictive Value of Tests; Salivary Gland Neoplasms; Transcription Factors; Translocation, Genetic; Young Adult
Publisher
W.B. Saunders
Type
journal article