The occurrence of cutaneous plasmacytomas unassociated with underlying multiple myeloma is rare. Only eight such cases have been reported in the literature. A patient who had a primary cutaneous plasmacytoma of the buttock for over 20 years is described. Clinical and laboratory examination failed to disclose multiple myeloma.
LaPerriere RJ, Wolf JE, Gellin GA. Primary Cutaneous Plasmacytoma. Arch Dermatol. 1973;107(1):99-100. doi:10.1001/archderm.1973.01620160067020