ORAL MELANOACANTHOMA: A RARE CASE OF DIFFUSE ORAL PIGMENTATION IN A CHILD

An 11-year-old female, melanodermal, was referred to stomatology service to evaluate a diffuse, brownish macule on the oral mucosa, asymptomatic, with a 7-day course. The intra-oral examination revealed brownish macules in the upper gingiva inserted, dark brown macule involving gingival inserted between teeth 32 and 36, left alveolar mucosa, and lip mucosa. The diagnostic hypotheses were physiologic pigmentation, oral melanoacanthoma, and melanoma. An incisional biopsy was performed on the region of the left buccal mucosa. Histologic sections revealed a mucosal fragment layered by squamous, stratified, parakeratinized epithelium with areas of acanthosis and the presence of numerous dendritic melanocytes between the cells of the upper layers. Based on these findings, the lesion was diagnosed as oral melanoacanthoma. During the follow-up of 15 days and 30 days, a partial regression of the lesion was observed. After 4 months of the diagnosis, complete regression of the lesion was observed.