F-18 FDG PET Imaging of GVHD-Associated Polymyositis

F-18 FDG PET imaging has an established role in the management of lymphoma patients, many of whom receive hematopoietic stern cell transplantation (HSCT). Myositis is a rare manifestation of chronic graft-versus-host disease (GVHD), a common complication of HSCT. We present a case of GVHD-associated polymyositis presenting as intense, diffuse muscle uptake on F-18 FDG PET. The patient is a 35-year-old man with a history of recurrent Hodgkin disease. He presented with low-grade fever, malaise, and diffuse musculoskeletal pain just less than 5 years after HSCT. Chronic GVHD-associated polymyositis is readily treatable with immunosuppressive therapy. Without treatment it can have devastating consequences, notably myoglobin-induced renal failure. Therefore, the interpreting physician should have familiarity with this potential scan finding as suggestive of a treatable complication of HSCT.