Relapsing IgD Myeloma with Increased Circulating Plasma Cells: Clinical Case Report and Literature Review.

IgD myeloma is a rare subset of multiple myeloma characterized by the production of monoclonal IgD protein. This subset of myeloma generally has a more severe and aggressive clinical course. The case reported here is of a 61-year-old female with recurrent disease complicated by encephalopathy, myalgia, and extensive skeletal involvement. The bone marrow showed sheets of plasma cells and plasmablasts, with flow cytometry demonstrating a monoclonal population of CD138-positive, lambda-restricted cells. FISH demonstrated a t(11;14)(q13;q32) translocation and a gain of 1q. Despite treatments with daratumumab, bortezomib, lenalidomide, dexamethasone, and autologous stem cell transplant, the patient ultimately expired from streptococcal pneumonia with hypoxic respiratory and subsequent multiorgan failure.