A 33-year-old woman presented with progressive visual loss. An MRI examination revealed a pituitary lesion which was suspicious of abscess. FDG and F-2-fluorodeoxysorbitol (F-FDS) PET were performed to differentiate malignancy from inflammation. FDS is a new tracer with potential in differentiating inflammatory tissues based on results from animal studies. However, intense tracer uptake was found in the pituitary in both PET studies. The lesion was proved to be spindle cell carcinoma following biopsy.