Late onset dermal melanocytosis: an upper back variant.

Seven elderly Japanese men with blue macules on their upper backs are reported. Histological examination showed this pigmentation to be melanosis due to the presence of spindle-shaped or oval pigment-laden cells in the dermis. Electron microscopy revealed the cells to be compatible with dermal melanocytes. We assume that this condition belongs to the category of late onset dermal melanocytosis and is an upper back variant. This concept has not been proposed before.