68Ga-PSMA-11 PET/CT in a Case of Isolated Parietal Peritoneal Metastasis From Prostate Adenocarcinoma.

Isolated peritoneal metastasis of prostate cancer is extremely rare. We present 68Ga-PSMA-11 PET/CT findings in a case of isolated parietal peritoneal metastasis from prostate adenocarcinoma 35 months after radical prostatectomy. The peritoneal metastases showed multifocal intense PSMA uptake, but subtle structural abnormalities on 68Ga-PSMA-11 PET/CT. The patient was subsequently treated with androgen deprivation therapy. The peritoneal metastases progressed 25 months after the initiation of androgen deprivation therapy and were removed surgically. Histologic and immunohistochemical evaluation revealed metastatic prostate adenocarcinoma with treatment-related neuroendocrine differentiation. This case demonstrates the usefulness of 68Ga-PSMA-11 PET/CT in identifying atypical metastasis from prostate adenocarcinoma.