Mucosal melanotic macule, reactive type: a simulation of melanoma.

Two patients with spontaneously resolving hyperpigmented patches of the oral mucosa are reported. Histologically, lesions in both cases showed large pigment-laden dendritic cells singly dispersed at all levels of the epidermis, which simulated in situ melanoma. The absence of such cells in the basal layer of the epidermis served to histologically distinguish these lesions from a biologically malignant melanocytic tumor. Spontaneous resolution in both patients suggests that the condition is reactive. We propose the term mucosal melanotic macule, reactive type, for this lesion, which has been described previously under the misnomer oral melanoacanthoma.