[Cylindroma on a pleomorphic adenoma. Apropos of 2 case reports]

Among a group of 863 patients with epithelial tumors of the salivary glands, including 470 with pleomorphic adenomas, the latter were associated with carcinomas in 20 cases and of these two were adenoid cystic carcinoma. In both cases these were isolated parotid tumors, lacking functional symptomatology and failing to recur 2 and 4 years respectively after parotidectomy. Diagnosis was mainly by histology and was based on the finding of a co-existing pleomorphic adenoma and an authentic adenoid cystic carcinoma, not to be confused with the benign pseudo-cylindromatous appearance sometimes detected in simple pleomorphic adenomas. This association of adenoid cystic carcinoma and pleomorphic adenoma increases the risk of recurrence and of metastases--long-term follow up is necessary. Prognosis is dependent mainly on the quality of the initial surgical excision.