MYOEPITHELIOMA ON SOFT PALATE -A CASE REPORT-

연구개에 발생한 근상피종 1예 -증례보고-

Myoepithelioma is composed exclusively of myoepithelial cells. Myoepithelial cells are ectodermally derived contractile cells that can be routinely identified in many normal tissues having secretory function such as major and minor salivary glands, lacrimal gland and sweat gland. Tumors composed exclusively of myoepithelial cells, so-called myoepitheliomas, are rare-less than 1% of all salivary gland tumors. Grossly, these tumors are well demarcated. The external surface is smooth and may be bosselated. The cut surface is white and homogenous. Microscopically, these tumors are surrounded by a thin fibrous capsule. They are composed of benign-appearing spindle- shaped and/or polygonal cells. Mitoses are rare. Frequently these tumors contain myxomatous stroma which is susceptible to alcial blue stain. Clinically, myoepitheliomas present as slow-glowing, painless masses and can not distinguished from pleomorphic adenomas. Treatment is the same as for pleomorphic adenoma, and the surgical excision should include a margin of normal tissue. Although the majority of myoepitheliomas have behaved in a beingn manner, pleomorphism and mitotic activity have been associated with local aggressiveness.