Early response to treatment with Glivec detected with 18F-FDG PET in a patient with gastrointestinal stromal tumor

We present the case of a male patient with gastrointestinal stromal tumor (GIST) in whom we conducted two (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) studies, the first one prior to beginning the treatment with Glivec and the second after one month of treatment. The first (18)F-FDG PET scan detected multiple FDG avid foci in distal esophagus, liver and in an interaortocava lymph node. The second (18)F-FDG PET showed very good response to therapy, with an almost complete disease remission. After 23 months of follow-up, the early response to treatment detected by (18)F-FDG PET was confirmed. The utility of (18)F-FDG PET in the evaluation of response to treatment in GIST is discussed and compared with CT.