Myoepithelioma is a relatively rare form of salivary gland
tumor composed entirely of myoepithelial cells. This
tumor was formerly considered to be a subtype of
pleomorphic adenoma; however, in the latest World Health Organization classification of 1991 it is listed as an independent entity. We report herein an extremely rare case of
myoepithelioma of the upper lip. A 78-year-old Japanese female presented with a huge, painless mass on her upper lip. CT and MRI revealed a 50 x 40 mm(2) well-defined ovoid
tumor. A benign minor salivary gland
tumor was clinically suspected, and the patient underwent complete resection of the
tumor under
general anesthesia. The surgical defect was immediately reconstructed using an Abbe-Estlander flap. The
tumor was histopathologically diagnosed as a benign
myoepithelioma of the minor salivary gland. Immunohistochemically, the
tumor cells were positive for
vimentin, cytokeratins, alpha-smooth muscle actin and
S-100 protein, confirming the morphological diagnosis of
myoepithelioma. The patient's postoperative
clinical course was uneventful, and satisfactory results were obtained both functionally and esthetically. The pathology, clinical manifestations and treatment of
myoepithelioma are reviewed.