Detection of Unusual Peritoneal Metastases of Prostate Cancer With 68Ga–Prostate-Specific Membrane Antigen PET/CT

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

ABSTRACT

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.

Peritoneal Metastases From Prostate Carcinoma Treated With 177 Lu-PSMA-I&T

ABSTRACT

A 71-year-old man was referred for 177 Lu-PSMA therapy. He had metastatic castration-resistant prostate cancer, progressive on several treatment lines, with current PSA 260 μg/L and deteriorating condition. CT showed ascites with omental and peritoneal metastases, all positive on PSMA PET/CT. He was treated with 4 cycles of 7.4 GBq (0.2 Ci) 177 Lu-PSMA-I&T. Posttherapy scans showed good targeting of all metastases. After 4 cycles, PSA had dropped to 44 μ/L. Four months after the fourth cycle, the patients' general condition had significantly improved, and PSA had decreased to 7.0 μg/L.

Detection of Diffuse Peritoneal and Omental Metastases From Prostate Cancer With 18F-PSMA-1007 PET/CT

ABSTRACT

Diffuse peritoneal and omental infiltration of prostate cancer detected by 18F-PSMA-1007 PET/CT was rarely reported. We report a case of an 80-year-old man who was suspected of prostate carcinoma metastasis and underwent 18F-PSMA-1007 PET/CT for restaging the disease. PET/CT imaging presented intense tracer uptake in the prostate gland, multiple lymph nodes, and bones. Interestingly, we found extremely increased radioactive uptake of diffuse peritoneum and omentum on 18F-PSMA-1007 PET/CT images, which are very rare metastatic sites for prostate cancer.

Rapidly Evolving Diffuse Omental Carcinomatosis of Prostate Cancer in 68Ga-PSMA PET/CT

ABSTRACT

An 81-year-old man received androgen deprivation therapy for a locally advanced prostate cancer and, 6 months later, a curative radiation therapy. Half a year later, the patient presented with a steeply increased PSA value (32 ng/mL) and a suppressed testosterone level (0.48 nmol/L). The consecutively performed 68Ga-PSMA PET/CT revealed, besides local tumor remains and several PSMA-positive lymph node and soft tissue metastases, an extensive, diffuse PSMA ligand accumulation in the omentum, which was immunohistochemically proven to be a carcinomatosis of prostate cancer. None of the extraprostatic lesions were present in the pretherapeutic PSMA PET 1 year ago.