The best way to approach this situation is as PET being done for fever of unknown origin. There is little evidence of recurrent lymphoma. The bone marrow has 2% of cells that may be monoclonal and no Fever of unknown origin (FUO) is among the most difficult medical puzzles to solve.PET appears to have a very high negative predictive value in ruling out inflammatory causes of fever.If positive, PET can direct attention to rareas of fartehr workup but does jnot reliably distinguish infetious, malaignant and inflammatory causes of fever.The limited data of prospective studies indicate that 18F-FDG PET has the potential to play a central role as a second-line procedure in the management of patients with FUO. In these studies, the PET scan contributed to the final diagnosis in 25% – 69% of the patients. In the category of infectious diseases, a diagnosis of focal abdominal, thoracic, or soft-tissue infection, as well as chronic osteomyelitis, can be made with a high degree of certainty. Negative findings on 18F-FDG PET essentially rule out orthopedic prosthetic infections. In patients with noninfectious inflammatory diseases, 18F-FDG PET is of importance in the diagnosis of large-vessel vasculitis and seems to be useful in the visualization of other diseases, such as inflammatory bowel disease, sarcoidosis, and painless subacute thyroiditis. In patients with tumor fever, diseases commonly detected by 18F-FDG PET include Hodgkin’s disease and aggressive non-Hodgkin’s lymphoma but also colorectal cancer and sarcoma. 18F-FDG PET has the potential to replace other imaging techniques in the evaluation of patients with FUO. Compared with labeled white blood cells, 18F-FDG PET allows diagnosis of a wider spectrum of diseases. Compared with 67Ga-citrate scanning, 18F-FDG PET seems to be more sensitive.
Lorenzen J, Buchert R, Bohuslavizki KH. Value of FDG PET in patients with fever of unknown origin. Nucl Med Commun 2001;22:779-83.
Knockaert DC, Vanderschueren S, Blockmans D. Fever of unknown origin in adults: 40 years on. J Intern Med 2003;253:263-75.
MELLER Johannes ; SAHLMANN Carsten-Oliver ; SCHEEL Alexander Konrad 18F-FDG PET and PET/CT in fever of unknown origin The Journal of nuclear medicine 2007, vol. 48, no1, pp. 35-45