Variant morphology in multiple myeloma.

A 45-year-old man presented to the clinic with the chief complaints of low back pain, marked weight loss, and pallor of 2 months duration. He was found to have severe normocytic anemia with leukoerythroblastosis. Bone marrow aspirate resulted in a dry tap. Marrow trephine biopsy showed findings initially interpreted as poorly differentiated carcinoma involving marrow. Immunohistochemistry and protein studies established a diagnosis of IgG Kappa multiple myeloma. Correlation of marrow biopsy findings with clinical, radiological and immunological data remain an essential part of the diagnostic evaluation of multiple myeloma.