Rectal Carcinoma on 68Ga-PSMA PET/CT

Area of Science:

• Oncology
• Nuclear Medicine
• Radiology

Background:

• Prostate-specific membrane antigen (PSMA) is a validated target for imaging and therapy in prostate cancer.
• Increasing evidence suggests PSMA can be expressed in non-prostate malignancies, requiring further investigation.

Observation:

• A case of biopsy-proven rectal carcinoma with significant PSMA uptake on Gallium-68 (Ga) PET/CT is presented.
• The uptake was noted during the workup for synchronous prostate cancer.

Findings:

• The rectal carcinoma demonstrated avid PSMA uptake, an unexpected finding in a non-prostate primary tumor.
• This observation aligns with a growing body of literature on non-prostatic PSMA expression in cancers.

Implications:

• Highlights the potential for false positives or misleading findings when interpreting PSMA PET/CT scans.
• Emphasizes the critical need for careful radiological assessment and consideration of differential diagnoses in cases of unsuspected PSMA activity.
• Suggests further research into the mechanisms and clinical significance of PSMA expression in diverse malignancies.