False Positive Uptake in Bilateral Gynecomastia on 68Ga-PSMA PET/CT Scan

Area of Science:

• Nuclear medicine
• Oncology
• Radiology

Background:

• Hormonal therapy is a common treatment for prostate cancer.
• Biochemical recurrence necessitates accurate staging and monitoring.
• Gallium-68 prostate-specific membrane antigen (Ga-PSMA) PET/CT is a key imaging modality for prostate cancer recurrence.

Observation:

• A 66-year-old man with prostate cancer on hormonal therapy presented with biochemical recurrence.
• Ga-PSMA PET/CT revealed expected tracer uptake in the prostate, lymph nodes, and bone lesions.
• Unexpectedly, moderate heterogeneous tracer concentration was observed in the bilateral breast parenchyma.

Findings:

• Clinical examination confirmed bilateral gynecomastia in the patient.
• The observed Ga-PSMA uptake in the breast parenchyma correlated with gynecomastia.
• This highlights a potential pitfall in interpreting Ga-PSMA PET/CT scans.

Implications:

• Ga-PSMA uptake is not exclusive to malignant tissue and can occur in benign conditions like gynecomastia.
• Radiologists and nuclear medicine physicians must consider benign causes of tracer uptake to avoid misdiagnosis.
• Accurate interpretation of Ga-PSMA PET/CT requires correlation with clinical findings and understanding of potential non-specific uptake patterns.