Solitary and multifocal oral melanoacanthoma

Background: Oral melanoacanthoma is a rare pigmented lesion characterized by sudden appearance and rapid radial growth, mimicking malignant melanoma. Oral melanoacanthoma may present as a solitary or multifocal lesion; however, the characteristics of these two clinical variants have never been addressed. In this study, we present an unusual case of multifocal oral melanoacanthoma and analyze cases of oral melanoacanthoma reported in the literature, with special emphasis on multifocal lesions. Methods: A thorough MEDLINE search of the literature for cases of oral melanoacanthoma was performed. The demographic and clinical data, histologic features, and immunohistochemical findings were extracted from the full-text articles. Results: The literature search yielded 52 patients with 67 lesions. The addition of our case increased this number to 53 patients with 72 lesions, 43 of whom had solitary lesions and 10 of whom had multifocal lesions. There was a female predominance amongst the patients with solitary oral melanoacanthoma (3: 1), whereas multifocal oral melanoacanthoma showed an equal gender distribution (1: 1). Multifocal lesions tended to occur more frequently on the palate, and solitary lesions on the buccal mucosa. Conclusions: Multifocal oral melanoacanthoma appears to demonstrate some demographic and clinical variations from the solitary type of lesion.