Incidental Finding of Spindle Cell Sarcoma on 68Ga-PSMA-11 PET/CT.

A 78-year-old man underwent 68Ga-prostate-specific membrane antigen-11 (PSMA-11) PET/CT for biochemical recurrence of prostate adenocarcinoma following a simple prostatectomy. The scan showed PSMA-avid local recurrence within the prostatectomy bed and a suspicious right internal iliac nodal metastasis. In addition, there was a mildly avid subcutaneous lesion in the right flank, which revealed high-grade spindle cell sarcoma at histopathology. This case represents a potential pitfall for PSMA-11 PET imaging. The presentation of mildly avid, atypical soft tissue lesions should warrant a biopsy to allow for proper diagnosis and treatment management.