Prostatic Utricle Cysts as a Potential Pitfall in PSMA PET/CT Interpretation

Area of Science:

• Oncology
• Nuclear Medicine
• Radiotherapy

Background:

• Prostate cancer management involves radiotherapy and monitoring using prostate-specific membrane antigen (PSMA) Positron Emission Tomography/Computed Tomography (PET/CT).
• Biochemical recurrence after initial treatment necessitates accurate staging and localization of disease.

Observation:

• A 60-year-old man with T2aN0M0 prostate cancer, treated with intensity-modulated radiotherapy, presented with biochemical recurrence 6 years post-treatment.
• 68Ga-PSMA-11 PET/CT showed focal radioactivity in the prostate's posterior midline, initially concerning for recurrence.
• Subsequent MRI identified the focus as a prostatic utricle cyst, a finding also noted on a prior 18F-piflufolastat PET/CT with negative biopsy results.

Findings:

• Prostatic utricle cysts can exhibit PSMA avidity, potentially leading to misinterpretation as recurrent prostate cancer on PSMA PET/CT scans.
• Despite the PSMA-avid focus, the patient's negative biopsy results indicated the absence of malignancy at that site.

Implications:

• This case underscores the importance of considering benign prostatic anomalies, such as utricle cysts, in the differential diagnosis of PSMA-avid lesions in prostate cancer patients.
• Accurate interpretation of PSMA PET/CT is vital to prevent misdiagnosis and guide appropriate treatment strategies, avoiding unnecessary interventions.
• Integration of imaging modalities like MRI with PSMA PET/CT can improve diagnostic accuracy in cases of suspected prostate cancer recurrence.