Ossifying parotid carcinoma ex pleomorphic adenoma: CT findings.

The CT appearance of a large necrotic carcinoma ex pleomorphic adenoma of the parotid gland is described. The tumour contained trabecular bone, which was correctly identified on a preoperative CT examination and which indicated the origin of the tumour to be a benign pleomorphic adenoma. This degree of macroscopic bone formation is rare in pleomorphic adenoma, and its demonstration by CT has not been previously reported.