IgA orbital plasmacytoma in multiple myeloma.

The authors report a case of orbital plasmacytoma in a 48-year-old man with known multiple myeloma. He presented with proptosis, diplopia, and decreased vision of the left eye for several weeks. He had been previously treated for IgA lambda multiple myeloma with chemotherapy, radiation, and autologous stem cell transplant. After a left orbitotomy, flow cytometry revealed a tumor rich in plasma cells expressing CD138 with equivocal lambda light chain expression. The patient underwent orbital radiation, with improvement of vision and disc edema OS. The patient is currently undergoing salvage chemotherapy for relapse of multiple myeloma. This is the third reported case of IgA myeloma involving the orbit.