Hyalinizing clear cell carcinoma (HCCC) is a very rare malignant salivary gland tumor and extremely difficult to diagnose. The case presented here was diagnosed as a rare case of HCCC of the cheek. The characteristics of the pathological findings of HCCC were discussed.
A 30-year-old Japanese female patient was first seen with swelling of the left cheek without spontaneous pain. When she was 18 years old, the buccal tumor was diagnosed as a mucoepidermoid carcinoma. When she was 24 and 27 years old, the same tumor was diagnosed as an adenoid cystic carcinoma. No metastasis to the lymph nodes of the neck was observed clinically. After chemotherapy and radiotherapy, excision of the cheek tumor was performed. Histopathological examination revealed that this case fulfilled the criteria of HCCC. Light microscopically, the predominant tumor cells were round to polygonal containing clear PAS-positive granules in the cytoplasm. The stroma was composed of hyalinized fibrous connective tissue. Electron microscopically, abundant glycogen granules were observed in the cytoplasm.
