A Patient of Multiple Myeloma with Absent M-spike on Serum Protein Electrophoresis and Elevated Serum-Free Light Chains: A Case Report and Literature Review

Multiple myeloma is a neoplasm described as an abnormal growth of plasma cells that outnumbers the other normal hematopoietic cells inside the bone marrow. Patients are diagnosed at a median age of 66-77 years with 37% of those with age less than 65. Unexplained bone pain (most commonly in back and ribs), pathologic fractures, fatigue, and weight loss are common initial symptoms at presentation. Here, we report a rare presentation of multiple myeloma with normal serum protein electrophoresis but elevated serum-free light chains. The absence of monoclonal gammopathy on protein electrophoresis or normal immunofixation does not negate the diagnosis of multiple myeloma. Therefore, all the sub types of multiple myeloma need to be comprehensively studied to aid in reaching an accurate diagnosis.