Intense Uptake in Amyloidosis of the Seminal Vesicles on 68Ga-PSMA PET Mimicking Locally Advanced Prostate Cancer.

We report a case of benign senile seminal vesicle amyloidosis demonstrating intense Ga-prostate-specific membrane antigen (PSMA) uptake on PET/CT. A 68-year-old man underwent staging PSMA PET/CT and MRI for biopsy-proven prostate adenocarcinoma. There was an intense focus of Ga-PSMA uptake in the primary malignancy, as well as symmetrical intense uptake in the seminal vesicles bilaterally that was reported as multifocal disease with local invasion. Final histology after radical prostatectomy showed amyloidosis of the seminal vesicles without any evidence of prostate cancer. Care should be taken in the interpretation of seminal vesicle PSMA uptake to avoid overstaging.