A case of premalignant melanosis of the palate.

Abstract

We have reported that most malignant melanomas of the oral mucosa are clinically and histologically identical to acral lentiginous melanoma (ALM) of the skin . There have been many studies of precusors of cutaneous melanoma, but few have mentioned oral melanoma.We describe our experience with a case of precancerous melanosis occurring in the hard palate . A 68-yearold woman was referred to our hospital because of a pigmented lesion of the palate, which her dentist had noticed accidentally. Clinical examinations revealed brownish-black plaque in the center of the lesion and adjacent light brown pigmented macules with no apparent borderline. She underwent surgical resection of the lesion via an intraoral approach for a diagnosis of a benign or premalignant melanocytic lesion . Histological examination revealed lentiginous or pagetoid proliferation of atypical melanocytes in the epithelial layer in the plaque lesion, with proliferation of dendritic melanocytes or simple hyperpigmentation in the macular lesion. These findings were identical to those of the radial growth phase of acral lentiginous melanoma of the oral cavity, which we reported previously. A diagnosis of a precursor lesion of ALM was made. She is free from disease 12 months after operation.