Multiple Myeloma in a 45-Year-Old Woman with Screening-Detected Anemia and Unintentional Weight Loss: A Case Report

Background and Clinical Significance: Anemia is commonly detected during health screening and may initially appear to be an isolated hematologic abnormality. Careful history-taking is important because associated symptoms may provide clues to serious underlying disease. We report a case of multiple myeloma in which unintentional weight loss was the key clinical clue during evaluation of screening-detected anemia. Case Presentation: A 45-year-old woman was referred for evaluation of anemia detected during routine health screening. Initial laboratory testing showed normocytic anemia without evidence of iron deficiency, vitamin B12 deficiency, or folate deficiency. Routine history-taking for anemia revealed unintentional weight loss of 3.5 kg (4.6% of her body weight) over three months, prompting evaluation for malignancy. Non-contrast computed tomography demonstrated an osteolytic lesion in the manubrium. Serum protein electrophoresis showed an M-peak, and immunofixation detected an IgA-kappa monoclonal protein and urinary kappa-type Bence Jones protein. Serum free light-chain testing revealed a markedly elevated kappa/lambda ratio. At the referral hematology department, bone marrow aspiration showed 77.8% plasma cells, and biopsy and clot sections showed extensive infiltration by CD138-positive plasma cells, consistent with plasma cell myeloma. She subsequently received chemotherapy at the referral hospital, achieved remission, and has returned to work. Conclusions: Unintentional weight loss can serve as an important red flag when evaluating non-iron-deficiency anemia detected through health screening. Actively eliciting weight change may facilitate prompt diagnosis of an otherwise unsuspected hematologic malignancy.