Histologically benign pleomorphic adenoma of the calvaria.

Pleomorphic adenoma or benign mixed tumor is the most common salivary gland tumor. It is most frequently located in the parotid gland, and is considered to be a benign neoplasm accounting for 70-80% of all benign tumors of the salivary glands [1]. Benign metastasizing pleomorphic adenoma is extremely rare, with only a handful of cases described. We report a case of a histologically benign mixed tumor in the diploic space of the skull in a patient who had a benign pleomorphic adenoma (BPA) of the parotid gland resected 16 years previously. This case may represent an unusual example of a histologically benign mixed tumor of salivary origin metastasizing to the calvaria without evidence of local recurrence, a previously unreported phenomenon . An alternative, less likely, possibility would be a metachronous chondroid syringoma arising from displaced cutaneous adnexal structures.