ABSTRACT
A 59-year-old man with pancytopenia underwent 18F-fluorodeoxyglucose positron emission tomography/computed tomography for suspected carcinomatosis. The scan revealed diffuse bone marrow uptake, prompting further investigation. Bone marrow analysis revealed no malignant cells; however, erythroblasts with cytoplasmic vacuolization were observed. Subsequent testing showed low serum copper and ceruloplasmin levels, indicating copper deficiency. Copper supplementation resulted in significant improvement in cytopenia. Notably, the bone marrow uptake on subsequent scans decreased significantly. This case highlights the importance of considering copper deficiency as a potential cause of diffuse bone marrow uptake of 18F-fluorodeoxyglucose on positron emission tomography/computed tomography.