An Unexpected Seminal Vesicle Pitfall in PSMA PET

Area of Science:

• Nuclear medicine imaging
• Urology
• Oncology

Background:

• Prostate cancer management often involves monitoring Prostate-Specific Antigen (PSA) levels.
• Gallium-68 PSMA-11-PET (PSMA PET) is a key imaging modality for detecting prostate cancer recurrence.
• Persistent PSA elevation necessitates further investigation to rule out residual or metastatic disease.

Observation:

• A 76-year-old male on hormone therapy for prostate cancer presented with a persistently detectable PSA level.
• Initial PSMA PET imaging showed no definitive tumor lesions.
• Delayed phase imaging revealed focal PSMA uptake in the right seminal vesicle.

Findings:

• The focal PSMA uptake in the seminal vesicle was associated with contrast accumulation on CT.
• These findings were ultimately attributed to urinary reflux.
• Urinary reflux was a consequence of a prior prostatic enucleation procedure for acute urinary retention.

Implications:

• This case highlights the potential for false positives in PSMA PET imaging.
• Understanding post-surgical anatomical changes is crucial for accurate interpretation of PSMA PET scans.
• Delayed imaging protocols may help differentiate true tumor uptake from benign conditions like urinary reflux.