Immunohistochemical features of multifocal melanoacanthoma in the hard palate: a case report.
BACKGROUND
Melanoacanthoma (MA) has been described in the oral mucosa as a solitary lesion or, occasionally, as multiple lesions. MA mainly affects dark skinned patients and grows rapidly, showing a plane or slightly raised appearance and a brown to black color. The differential diagnosis includes oral nevi, amalgam tattoos, and melanomas. We report here the case of a 58-year-old black woman who presented multiple pigmented lesions on the hard palate.


METHODS
Based on the differential diagnosis of melanoma, a punch biopsy (4 mm in diameter) was performed. The material was fixed in 10% formalin, embedded in paraffin, and stained with hematoxylin-eosin or submitted to immunohistochemical analysis. Immunohistochemistry using antibodies against protein S-100, melan-A, HMB-45, MCM-2, MCM-5, Ki-67 and geminin was performed. Immunohistochemical analysis revealed strong cytoplasmic immunoreactivity of dendritic melanocytes for proteinS-100, HMB-45 and melan-A.Positive staining for proliferative markers (MCM-2, MCM-5, Ki-67) was only observed in basal and suprabasal epithelial cells, confirming the reactive etiology of the lesion. The diagnosis was oral Melanoacanthoma (MA).


CONCLUSIONS
The patient has been followed up for 30 months and shows no clinical alterations. MA should be included in the differential diagnosis of pigmented lesions of the oral cavity.
Department of Biosciences and Oral Diagnosis, São José dos Campos Dental School, São Paulo State University (UNESP), São José dos Campos, São Paulo, Brazil.
Luis Felipe
LF
das Chagas E Silva de Carvalho
Vitor Hugo
VH
Farina
Luiz Antonio Guimarães
LA
Cabral
Adriana Aigotti Haberbeck
AA
Brandão
Ricardo Della
RD
Coletta
Janete Dias
JD
Almeida
D049309:Acanthoma / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000378:metabolism* / Q000473:pathology; D021362:Palate, Hard / Q000473:pathology*