Findings from histologic examination showed a nodular infiltrate of mature as well as immature plasma cells in the dermis, separated from the epidermis by a grenz zone (Figures 2 and 3). Results of immunohistochemical analysis showed overwhelming λ light chain positivity. The patient was unable to tolerate bortezomib and was not a good candidate for additional radiotherapy. Treatment with doxorubicin had failed, and she died of progressive disease 5 months later.
Primary cutaneous plasmacytoma is a rare B-cell lymphoma that occurs without MM on presentation. One-third of these cases will ultimately progress to generalized MM.1 Secondary cutaneous plasmacytoma (metastatic cutaneous MM) is a cutaneous plasma cell infiltrate that most commonly occurs, spontaneously, as a local extension of MM from underlying bone.1 In rare cases, lesions of secondary cutaneous plasmacytoma have also arisen in areas of local trauma (TISP).2-7