Cutaneous plasmacytosis is a rare condition affecting middle-aged individuals, characterized by multiple red-brown papules and plaques over the trunk. It has been reported mainly in Japan.
The condition is accompanied by polyclonal hypergammaglobulinemia and superficial lymphadenopathy. Lung or retroperitoneal involvement occurs rarely.
References
High ratio of IgG4-positive plasma cell infiltration in cutaneous plasmacytosis-is this a cutaneous manifestation of IgG4-related disease? Miyagawa-Hayashino A, Matsumura Y, Kawakami F, Asada H, Tanioka M, Yoshizawa A, Mikami Y, Kotani H, Nakashima Y, Miyachi Y, Manabe T. Hum Pathol. 2009 Apr 20. PMID: 19386351