Cutaneous plasmacytosis: a clinicopathologic study of 12 cases in Taiwan revealing heterogeneous underlying causes.

Background: Cutaneous plasmacytosis is clinically characterized by multiple pigmented papules and plaques that occur mainly on the trunk and many plasma cells in the lesional skin. Most of the cases reported have occurred in Japan. Whether cutaneous plasmacytosis is a unique reactive disease or a neoplastic condition has not been established.