Carcinoma ex pleomorphic adenoma with special reference to the prognostic significance of histological progression: a clinicopathological investigation of 41 cases

Aims: To investigate a large series of cases of carcinoma ex pleomorphic adenoma (CEPA) to determine prognostic factors. Methods and results: Thirty cases of CEPA associated with primary pleomorphic adenoma (PA) and 11 cases of CEPA associated with recurrent PA were investigated. The median follow-up was 57.7 months, and ranged from 4 to 156 months. Purely intraductal carcinoma was found in 15 cases. Intraductal and extraductal intracapsular carcinoma together was found in one case. Extracapsular carcinoma was found in 25 cases. Prognosis was good for CEPA that was purely intraductal, extraductal intracapsular, or up to 5 mm extracapsular, and poor for CEPA that was 8 mm or more extracapsular. There were relatively more cases of CEPA with extracapsular invasion of 8 mm or more from recurrent PA than from primary PA, and the prognosis for CEPA associated with recurrent PA was worse than that for CEPA associated with primary PA. Conclusions: The threshold for distinguishing minor extracapsular invasion with good prognosis from wide extracapsular invasion with poor prognosis is 5 mm. The worse prognosis for CEPA associated with recurrent PA indicates the necessity for close surveillance of patients with recurrent PA.