Vas Deferens and Inguinal Canal Metastasis of Prostate Cancer Revealed by 68Ga-Prostate-Specific Membrane Antigen PET/CT

Abstract

A 71-year-old man with prostate adenocarcinoma underwent 68Ga–prostate-specific membrane antigen (PSMA) PET/CT for staging. 68Ga-PSMA PET/CT showed the primary lesion along with bladder, rectum, bilateral seminal vesicle invasion, and metastatic pelvic lymph nodes with intense 68Ga-PSMA uptake. Also, PET/CT showed rarely seen bilateral vas deferens invasion and metastasis to the inguinal canal. These rare metastases may be indicative of poor biological behavior and prognosis.

An Unexpected Seminal Vesicle Pitfall in PSMA PET

“…PSMA accumulation in prostate and seminal vesicles as a possible cause of transurethral resection has been previously described in a case report 1 . However, in this patient, the use of ceCTU 2 made it possible to confirm that the origin of the PSMA deposit was not due to prostate cancer 3–5 or regional blood flow/vascular permeability, 4 but to urinary elimination of the radiopharmaceutical and its subsequent accumulation in the seminal vesicle due to urinary reflux as a consequence of the previous HoLEP procedure 6–8 . This finding shows us that we should be aware that seminal vesicle PSMA uptake can be a false-positive caused by reflux of urine into the seminal vesicles after enucleation of the enlarged prostate with techniques such as HoLEP.…”

Asymptomatic Prostate Cancer Metastasis in Rectal Mucosa Revealed by 18F-PSMA-1007 PET/CT

“…3 Prostate cancer metastasis to the rectal mucosa occurs through the lymphatics, which generally do not cause clinical symptoms; routine examinations with CT and magnetic resonance imaging would merely reveal subtle degrees of both thickening and edema of the intestinal wall. 4,518 F-PSMA is a radioactive tracer targeting PSMAs to precisely reveal tiny or hidden lesions and rare metastases of prostate cancer in vivo 6,7 and dynamically assessing the efficacy of treatment. 8 In this case, 18 F-PSMA PET/CT can identify related lesions with specificity, improve clinical staging accuracy, and dynamically evaluate treatment response to ameliorate the prognosis of prostate cancer patients.…”