Giant cell tumor of major salivary glands: report of three cases, one occurring in association with a malignant mixed tumor.

Three cases of a heterofore undescribed neoplasm of major salivary glands morphologically similar to giant cell tumor of bone are presented. All tumors were located in the parotid gland of adult individuals, and all patients are alive and well following surgical excision. One of the three cases was associated intimately with a malignant mixed tumor (carcinoma in pleomorphic adenoma). Ultrastructural and immunohistochemical studies failed to provide conclusive evidence about the specific nature of the tumor cells. The major salivary glands should be added to the long list of organs in which extraskeletal giant cell tumors have been observed, whether alone or in association with an epithelial malignancy.