[Unilateral multiple tumorous lesions of the parotid gland]

Multifocal tumors within the same parotid gland are very rare. We treated 13 patients with multiple tumorous lesions within the unilateral parotid gland. We evaluated the multiple nodules by CT-sialography or magnetic resonance imaging (MRI). These imagings showed clearly two or more distinct nodular-appearing lesions. Recurrent pleomorphic adenoma (6 patients) was predominant, followed by Whartin's tumor (3 patients). The other lesions were two differential parenchymal tumors (polymorphous low grade adenoma/adenoma) within the same gland, a malignant lymphoma, a squamous cell carcinoma metastatic to the gland, and a tuberculous lesion. On palpitation, 9 of the patients had an unilateral tumor, one a palpable parotid mass in the gland, and the other four had two or more tumors in the unilateral gland. The patients with intra-parotid lymph node and metastatic lesions had extra-parotid cervical adenopathy. The clinical features and the differential diagnosis of the unilateral multiple tumorous lesions of the parotid gland are discussed.