Clinicopathological and molecular study of 10 salivary gland clear cell carcinomas, with emphasis on rare cases with high grade transformation and occurring in uncommon sites

作者：Lanlan Xuan, Suxia Wang, Jianguo Wei, Jianwei Yuan, Honggang Liu · 发表于：Diagnostic Pathology · 年份：2022 · DOI：10.1186/s13000-022-01200-z · 被引用次数：13 · 研究领域：Salivary Gland Tumors Diagnosis and Treatment、Cancer and Skin Lesions、Salivary Gland Disorders and Functions

BACKGROUND: As a rare salivary gland malignancy, clear cell carcinoma (CCC) is easily misdiagnosed. This study identified the features that allow better recognition of the clinicopathological and molecular characteristics and the prognosis of CCC, focusing on high-grade transformation (HGT) in this tumor and cases arising in uncommon sites. METHODS: Clinicopathological and follow-up data for 10 CCC samples were retrieved. Immunohistochemical (IHC) staining was performed, and fluorescence in situ hybridization (FISH) was used to detect EWSR1 gene rearrangements, EWSR1-ATF1 gene fusions, and MAML2 gene rearrangements. RESULTS: Histologically, typical CCCs comprised bland polygonal or round cells with clear cytoplasm. In contrast with typical CCCs, HGT tumor cells exhibited nuclear pleomorphism, high nuclear-to-cytoplasmic ratios, high mitotic activity, and necrosis. Rare morphologic features such as pseudopapillae, gland-like spaces, and entrapped ducts were also observed. Occasionally, tumors involving the oral cavity might arise from the overlying epithelium of the mucosal surface. Immunohistochemically, all the cases expressed p63, p40, and CK5/6, while myoepithelial-related markers were uniformly negative in all cases. HGT exhibited a wild type p53 expression pattern. FISH demonstrated EWSR1 rearrangement (10/10) and EWSR1-ATF1 fusion (4/5); however, MAML2 remained intact (0/3). CONCLUSIONS: CCCs with HGT or occurring in uncommon sites are extremely rare. Combining morpholo...