Immunohistochemical features of multifocal melanoacanthoma in the hard palate: a case report

Abstract

BackgroundMelanoacanthoma (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.Case presentationBased 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).ConclusionThe 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.

Multifocal oral melanoacanthoma associated with Addison’s disease and hyperthyroidism: a case report

“…Treatment in cases of oral melanoacanthoma is not recommended. However, these lesions must be followed up and may sometimes spontaneously disappear or decrease in size (3,9,27). The lesions in the present case remained unchanged during follow-up; however, changes in the clinical pattern of the lesions and their prognosis were still unavailable due to the short follow-up time and absence of similar cases in the literature.…”

“…The first description of oral melanoacanthoma was as a single lesion, reported by Schneider in 1981, but reports of multiple lesions are available in the literature (9,21). These lesions are slightly elevated, brownish/ blackish, usually affecting female and melanodermic patients, and requiring no treatment, as in the patient described in this report.…”

“…Oral melanoacanthoma lesions may vary in color from dark brown to black and are often asymptomatic, although in some cases pain, itching, and burning may occur (5,9). The buccal mucosa is the most affected site, but the lesions may also be found on the palate, gingiva, and lip mucosa (5,7,10).…”

“…Histologically, oral melanoacanthoma is characterized by a proliferation of benign dendritic melanocytes across the epithelium, spongiosis, acanthosis, chronic inflammatory infiltrates, and eosinophils in the underlying connective tissue (9,11).…”

Clinical and histopathological study of the oral multifocal melanoacanthoma: A case report

“…Cutaneous melanoacanthoma was described for the first time by Bloch, in 1927, however, the term melanoacanthoma was introduced by Mishima and Pinkus in 1960 (1), observing that this lesion could occur in both the skin and mucosa, such as those of the oral cavity. The first case of oral melanoacanthoma (OMA) was published in 1981(2).…”