Pigmented lesions of the oral cavity: an update.

Oral pigmentation may be focal, multifocal, or diffuse. The lesions may be blue, purple, brown, gray, or black. They may be macular or tumefactive. Some are localized harmless accumulations of melanin, hemosiderin, or exogenous metal; others are harbingers of systemic or genetic disease; and some can be associated with life-threatening medical conditions that require immediate intervention. The differential diagnosis for any pigmented lesion is extensive, and can include examples of endogenous and exogenous pigmentation. Although biopsy is a helpful and necessary aid in the diagnosis of focally pigmented lesions, with diffuse presentations lesions require a thorough history and laboratory studies to establish a definitive diagnosis.