Extremely Rare Prostate Metastasis From Rectal Carcinoma Detected on ⁶⁸Ga-FAPI PET/CT

Area of Science:

• Oncology
• Urology
• Medical Imaging

Background:

• Prostate metastases from colorectal adenocarcinoma are rare.
• They typically arise from local extension, not distant spread.
• This case presents a unique instance of distant prostate metastasis from rectal cancer.

Purpose of the Study:

• To report a rare case of prostate metastasis from rectal adenocarcinoma.
• To illustrate the diagnostic utility of ⁶⁸Ga-FAPI PET/CT in identifying such metastases.
• To discuss the clinical presentation and diagnostic challenges.

Main Methods:

• Case report of a 52-year-old male with a history of rectal adenocarcinoma.
• Clinical evaluation including assessment of lower urinary tract symptoms, serum creatinine, prostate-specific antigen (PSA), and cancer embryonic antigen (CEA).
• Diagnostic imaging with whole-body ⁶⁸Ga-FAPI PET/CT followed by prostate biopsy.

Main Results:

• The patient presented with lower urinary tract symptoms and elevated creatinine.
• Colonoscopy showed no local recurrence, but CEA levels were high.
• ⁶⁸Ga-FAPI PET/CT revealed diffuse prostate uptake, confirmed as metastatic adenocarcinoma on biopsy.

Conclusions:

• Metastatic involvement of the prostate by colorectal adenocarcinoma can occur as true distant spread.
• ⁶⁸Ga-FAPI PET/CT is a valuable tool for detecting prostate metastases from colorectal cancer.
• This case underscores the importance of considering unusual metastatic patterns in cancer patients.