Nasopharyngeal hyalinizing clear cell carcinoma with EWSR1 rearrangements diagnosed by fluorescence in situ hybridization.

Hyalinizing clear cell carcinoma (HCCC) is a rare, low-grade salivary gland neoplasm with a predilection for the palate and tongue. A 63-year-old woman presented a 14x14x17-mm mass at the roof of the nasopharynx. Endoscopic resection was performed via a transnasal approach. Histopathological findings of the salivary gland tumor indicated hyalinization of the stroma and neoplastic cells with clear cytoplasm without mucin. Fluorescence in situ hybridization analysis revealed that the tumor cells were positive for EWSR1 rearrangement. We finally diagnosed this case as HCCC of the nasopharynx. EWSR1 rearrangements are non-existent in other salivary gland tumors with clear cell change; thus, the identification of this rearrangement was very useful in accurately diagnosing HCCC.