CT Findings of Parotid Gland Tumors: Benign versus Malignant Tumors

ABSTRACT

PURPOSE: The purpose of this study is to evaluate the characteristics of parotid gland tumors to help in the differentiation between benign and malignant lesions. MATERIAL AND METHODS: The CT findings of 22 patients with surgically proven parotid gland tumors were reviewed. Analysis was focused on the density and margin characteristics of the tumors, and the relationahip between the tumor and surrounding structures. RESULTS: Those tumors were pleomorphic adenoma (n=8), Warthin's tumor (n=5), basal cell adenoma (n=l), lipoma (n=l), dermold cyst (n=l), adenold cystic carcinoma (n=2), mucoepidermoid carcinoma (n=l), epidermold carcinoma (n=l), and carcinoma in pleomorphic adenoma (n=l). Most of benign and malignant tumors were heterogeneous in denstiy on contrast enhanced CT scans. In 5 of 6 malignant cases, the tumors had irregular or ill-defined margin and a tendancy to involve or cross the superficial layer of deep cervical fascia with obliteration of subcutaneous fat. Two malignant tumors invaded surrounding structures. CONCLUSION: Although the heterogeneous density of tumor is not a specific finding for malignancy at CT, following findings, such as, irregular or blurred margin of the lesion, the involvement of fascial plane, and the infiltration of surrounding structures may suggest the possibility of malignant parotid tumor.