Carcinomatous change in the cranial metastasis from a metastasizing mixed tumor of the salivary gland--case report.

A 57-year-old female who had had a mixed tumor of the submandibular gland for 30 years presented with a cranial metastasis in the ipsilateral occipital region. Detailed histological examinations of the primary tumor failed to detect any carcinomatous component. In contrast, the metastasis contained a carcinomatous component. This histological discrepancy was confirmed by assessment of the expression of Ki-67 antigen in these tumor specimens and comparison with five typical benign mixed tumors. Cranial metastasis of a histologically benign mixed tumor is extremely rare, and a carcinomatous change in the metastatic tumor is apparently unique.