Clear Cell Myoepithelioma of Palate with Emphasis on Clinical and Histological Differential Diagnosis

Abstract

Myoepitheliomas account for less than 1% of all salivary gland tumors and mostly occur in the parotid gland and palate. A 58-year old male patient reported to the Outpatient Department of PMS College of Dental Science and Research (Kerala, India) with a slow growing painless swelling on the palate for 4 years. Pleomorphic adenoma, basal cell adenoma, myoepithelioma, cyst adenoma, lipoma, neurofibroma, neurilemmoma and leiomyoma were considered. Histopathology revealed a thinly encapsulated tumor composed mainly of sheets of clear cells mixed with cells having eosinophilic cytoplasm. Histopathological differential diagnosis included pleomorphic adenoma, oncocytoma, oncocytic hyperplasia, sebaceous adenoma, malignant salivary gland neoplasms and metastatic lesions from kidney and thyroid. Myoepitheliomas mostly occur in the parotid gland and palatal region and various histological types of myoepithelioma are described. Myoepitheliomas of the palate are rare with clear cell variant even rarer.