The Difference in the Clinical Features Between Carcinoma ex Pleomorphic Adenoma and Pleomorphic Adenoma.

Carcinoma ex pleomorphic adenoma (CXPA) arises from the primary or recurrent benign pleomorphic adenoma. The purpose of this study was to evaluate the clinical features that could be referenced in the differentiation. The medical records of 221 patients with pleomorphic adenoma and 15 patients with CXPA were retrospectively reviewed. Clinical characteristics, computed tomography and magnetic resonance imaging findings, and surgical pathology were analyzed. Patients with CXPA were older (55.1 vs 42.3; P < .01). Carcinoma ex pleomorphic adenoma was observed at higher rates in the minor salivary glands (24.9% vs 2.7%) and higher incidence of regional lymph node enlargement (P = .04). While all CXPA showed a low-to-intermediate mean apparent diffusion coefficient value (ADC), most of pleomorphic adenoma had an intermediate-to-high (P = .01). From this study, the following features should be considered as the clinical features of CXPA: (1) old age; (2) minor salivary gland tumor; (3) regional lymph node enlargement (>5 mm); and (4) low ADC findings.