Penile metastasis of prostate cancer imitating Peyronie's disease detected on [68Ga]Ga-PSMA-11 PET/CT

Abstract [ 68 Ga]Ga-PSMA-11 PET/CT (Gallium prostate-specific membrane antigen positron emission tomography/computed tomography) is an established molecular imaging technique for identifying the spread of prostate cancer in patients with biochemical recurrence (BCR) and for initial staging. Penile metastases from prostate cancer are very rare and can be easily misdiagnosed as noncancerous nodules as part of Peyronie's disease. Most cases of penile metastases occur in patients with disseminated disease and are typically diagnosed at advanced stages. In this case, a 74-year-old patient with prostate cancer underwent a successful prostatectomy, ADT, and radiation therapy to the prostate bed, achieving a PSAnadir of 0.01 ng mL −1 . Three and a half years after surgery, biochemical recurrence occurred, and the patient was referred to our clinic for a [ 68 Ga]Ga-PSMA-11 PET/CT scan. PET/CT revealed pathological PSMA expression in a proximal part of the penile root, later confirmed by pathohistological analysis as prostate cancer metastasis. Notably, our patient had a PSA value of only 0.53 ng mL −1 , one of the lowest serum PSA values reported in the literature for penile metastasis. This case underscores the critical role of [ 68 Ga]Ga-PSMA-11 PET/CT in differentiating benign conditions like Peyronie's disease from metastatic lesions and in detecting rare and unusual metastatic sites.