[Clinicopathological features of clear cell carcinoma of salivary gland in the head and neck].

To investigate the clinical, histologic, immunohistochemical (IHC) and molecular genetic features of clear cell carcinoma (CCC) of salivary gland in the head and neck regions. Seven cases of CCC diagnosed in the Department of Pathology, the First Affiliated Hospital of Nanjing Medical University from 2018 to 2021 were included. The clinical and pathologic data, HE sections and IHC staining were reviewed, and EWSR1 gene translocation was detected by fluorescence in situ hybridization (FISH). The relevant literature was also reviewed. There were five males and two females, with an age range of 32 to 71 years (mean 50 years). The tumors were located in the palate, base of tongue, subglottic, right submaxillary and nasopharynx. Histologically the tumors were composed of sheets, nests, and trabecular of large, monomorphic cells which possessed abundant clear and eosinophilic cytoplasm. The stroma was characterized by abundant hyalinized fibrous strands admixed with cellular fibrous (desmoplastic) tissue. The tumor growth was infiltrative. IHC staining revealed positivity for CKpan and squamous cell immunophenotypic markers (CK5/6, p63 and p40), but negativity for myoepithelial markers (SMA, calponin, GFAP and CD10). The EWSR1 gene translocation was detected by FISH. The prognosis was excellent, with the follow-up periods ranging from 8 months to 33 months. During this period, six patients survived without tumor, only one patient with cervical lymph node metastasis. CCC of salivary gland is rare and needs to be differentiated from various other types of tumors containing clear cells. Awareness of the histopathologic characteristics, and combined with IHC and molecular genetic examination can avoid misdiagnosis. The biological behavior of the tumor is indolent with a good overall prognosis.