Prostate Cancer Recurrence Due to Isolated Testicular Metastases Detected by PSMA PET/CT.

Prostate cancer is the most common solid malignancy to metastasize to the testicles, although testicular metastases remain rare and are often discovered only postmortem. Retrospective analysis of 95 Ga-prostate-specific membrane antigen (PSMA) PET/CT reports from September 2016 to July 2024 using scrotal region search terms identified 30 patients with indeterminate findings and 6 patients with pathology-confirmed testicular metastases. Data on imaging, pathology, clinical outcomes, and prostate-specific antigen values were reviewed. Ga-PSMA PET/CT detected isolated testicular metastases in 6 patients with M0 castrate-sensitive prostate cancer after maximal pelvic therapy who were imaged because of rising prostate-specific antigen levels. Three of the 6 patients did not have ultrasound abnormalities. Five of the 6 patients were treated with orchiectomy and had durable responses (median follow-up, 33 mo; range, 10-58 mo). Including the testes in field of view of the PSMA PET scan may avoid false-negative results. Ga-PSMA-avid testicular and peritesticular lesions may indicate metastasis even with a negative ultrasound. Orchiectomy can result in durable remissions for these patients.