Clear cell carcinoma, not otherwise specified, of salivary glands: a clinicopathologic study of 4 cases and review of the literature.

Clear cell carcinoma, not otherwise specified (CCC-NOS), is a recently described rare malignant salivary neoplasm. We report the clinicopathologic and immunohistochemical features of 4 cases. The results were then analyzed collectively with the approximate 60 cases of CCC-NOS reported in the English-language literature to define the characteristics of this unusual neoplasm. Combining our cases with those in the literature, a total of 66 cases, confirms that CCC-NOS is a low-grade malignant neoplasm with distinctive clinical and pathologic features. It arises primarily in the minor salivary glands (91% of cases), particularly in the palate or base of tongue, and usually occurs in patients >30 years of age (mean 54.2 years) with a female-to-male ratio of 1.4:1; 12.3% of patients experience local recurrences, 19.3% develop positive regional lymph nodes, 8.8% have distant metastases, and 3.5% die of the disease. Immunohistochemical study focusing on tumor differentiation was performed for our cases, and the findings support the concept that CCC-NOS is of ductal epithelial origin without myoepithelial cell participation.