18F-FDG PET/CT Imaging of Prostate Stromal Tumor of Uncertain Malignant Potential.

A 79-year-old man presented with dysuria and increased serum prostate-specific antigen level (21 ng/mL). MRI revealed bulky prostate enlargement but was inconclusive in revealing neoplastic lesions. Nevertheless, because of high clinical suspicion for neoplasm, transrectal biopsy revealed stromal tumor of uncertain malignant potential mixed with foci of low-grade primitive prostate stromal sarcoma. 18F-FDG PET/CT showed high FDG uptake consistent with neoplasm in the lower part of the hypertrophic prostate gland and focal areas of elevated FDG uptake, consistent with metastases in the spine, ribs, and femur.