Carcinoma ex-Pleomorphic Adenoma: a Clinicopathological and Immunocytochemical Analysis

Objective: To analyze the clinicopathological and immunohistochemical features of carcinoma ex pleomorphic adenoma (CAxPA) in the parotid region. Methods and Results: Thirteen cases of patients with pathological diagnosis of "parotid gland carcinoma in pleomorphic adenoma" were collected, with a mean age of (62.62±12.06) years. The clinical presentation, cytology, and immunohistochemistry were analysed. The tumours were found to be present for periods ranging from 1 week to 30 years. Only one patient had symptoms of facial nerve injury at the time of admission. Immunohistochemical results were as follows: all patients were positive for CK14, TDGF-1, Nrf2, P120, and AE1/AE3. COX-2, E-cadherin, CK5/CK6, S-10, CK, P53 were partially positive, and Ki-67 ranged between 2%-60%. All patients were treated with surgery, four patients received postoperative radiotherapy, and one patient each developed postoperative recurrence and metastasis. Conclusion: Carcinoma ex pleomorphic adenoma (CAxPA) is relatively rare. It is necessary to make a definite diagnosis to avoid missed diagnosis of malignant components in PA. Exploring its specific immunohistochemical indices can provide valuable clinical data, aiding in the differential diagnosis, so as to guide further clinical treatment and determine its prognosis.