Carcinoma ex pleomorphic adenoma without malignant findings upon clinical in the palate

Carcinoma ex pleomorphic adenoma (CXPA) generally develops from long-standing and recurrent cases of pleomorphic adenoma (PA). As a salivary gland tumor, the histopathological finding is vary, and the diagnosis of a benign or malignant tumor may not be reflected by imaging data. We here present a case of CXPA in the palate that showed no malignant findings upon clinical, imaging and histopathological examination of a biopsy specimen, but that was confirmed to be malignant upon surgical resection. A 72-year-old man was referred with a painless mass in the right-side palate that exhibited increasing swelling. Histopathological and immunostaining investigations of the biopsy specimen revealed PA, in addition to clinical and imaging evaluation. However, as that was may be malignant considering the prolonged course the onset, we informed to patients for possible postoperative dilation surgery and adjuvant therapy. Histopathological diagnosis of the resected specimen was CXPA with an intra-capsular carcinoma. The carcinoma component was a mucoepidermoid carcinoma. The clinical course of this patient provided two important insights. First, CXPA in the palate can present findings indicative of PA in clinical examination and imaging. Second, surgical management for PA considering the potential for CXPA was beneficial. In cases of PA that onset was suspected to be many years previous, surgical management should be undertaken that considers the potential presence of CXPA, even if the preoperative diagnosis does not suggest malignancy.