Giant cell arteritis mimicking multiple myeloma; diagnosed by PET scan

This case report describes a patient who presented with severe anemia, monoclonal gammopathy, a high erythrocyte sedimentation rate and significant weight loss. These features were highly suggestive of multiple myeloma. Bone marrow aspiration was negative for myeloma on two occasions. A positron emission tomography (PET) scan showed extensive 2-flourodeoxy-glucose uptake in the vascular tree consistent with arteritis. A temporal artery biopsy established the diagnosis of giant cell arteritis (GCA). There were no typical symptoms of GCA, such as headache, visual disturbance, or polymyalgia rheumatica. The patient was treated with steroids, which resulted in the resolution of anemia, monoclonal gammapathy, and other symptoms.