Melanotic Oncocytic Metaplasia of the Nasopharynx: A Report of Three Cases and Review of the Literature

Melanotic oncocytic metaplasia of the nasopharynx is a rare condition which is characterized by the presence of usually a small, brown to black colored pigmented lesion around the Eustachian tube opening. Although it is a benign lesion, it may be clinically misdiagnosed as malignant melanoma. Microscopically, melanotic oncocytic metaplasia is a combination of oncocytic metaplasia of the epithelium of the gland and melanin pigmentation in its cytoplasm. In our present study, we report three cases of melanotic oncocytic metaplasia of the nasopharynx. All the three cases occurred in men and were presented as multiple black pigmented lesions around the torus tubarius. Microscopically, mucous glands with diffuse oncocytic metaplasia and numerous black pigments were observed. No cellular atypia was observed. Immunohistochemically, the scattering of S-100 protein-positive, and human melanoma black 45-negative dendritic melanocytes was evident. This is the first report of cases of melanotic oncocytic metaplasia of the nasopharynx in Korea.