A Case of Plasma Cell Myeloma with Multilobated and Monocytoid Morphology

Plasma cell myeloma (PCM) accounts for approximately 1% of malignant tumors and 10 to 15% of hematological neoplasms. It is a malignant disease characterized by abnormal proliferation of plasma cells and monoclonal immunoglobulins or free light chains (FLCs). There are many morphological variations of the myeloma plasma cells which include mature, immature, plasmablastic, and pleomorphic types. Here, we report a rare presentation of PCM with normal serum protein electrophoresis but elevated serum FLCs and having convoluted, multilobated, and monocytoid morphology. This type of morphology is related to an aggressive clinical course and resistance to conventional chemotherapy. Moreover, absence of M protein in serum/urine electrophoresis does not rule out the diagnosis of PCM and serum FLC assays plays an important role in this kind of scenarios.