RESUMO
Multiple myeloma (MM) commonly presents with anemia and bone pain. Besides bone marrow involvement, MM has a tendency to involve other organs with gastrointestinal (GI) tract, especially lower GI tract involvement being uncommon. Our case shows an elderly male with anemia due to suspected GI malignancy. Investigations revealed anemia, thrombocytopenia, positive stool occult blood and inconclusive diagnostic endoscopic findings. An elevated serum total protein, serum calcium and serum creatinine gave rise to the suspicion of MM which was later supported by the fulfilment of the CRAB criteria, expressed as hypercalcemia, renal failure, anemia and lytic lesions on skull X-ray. The relationship between multiple myeloma and GI bleeding is rare and indicates extramedullary disease which is a sign of poor prognosis. Early detection may alter the prognostic course of MM.