Ovulation and increased FDG uptake on PET: potential for a false-positive result

Area of Science:

• Oncology
• Nuclear Medicine
• Radiology

Background:

• F-18 FDG PET is a valuable tool for staging and monitoring malignant diseases.
• Physiological uptake of F-18 FDG can mimic pathological processes, leading to false-positive findings.
• Accurate interpretation of PET scans is crucial for appropriate patient management.

Observation:

• A case is presented of a patient with a history of urethral squamous cell carcinoma.
• F-18 FDG uptake was observed in the right ovary.
• This uptake was correlated with physiological activity during ovulation.

Findings:

• Physiological ovarian uptake of F-18 FDG can occur in females of reproductive age.
• This normal activity can be misinterpreted as malignant recurrence or metastasis.
• Careful evaluation is needed to differentiate physiological from pathological uptake.

Implications:

• Clinicians must maintain a high suspicion for physiological ovarian uptake in women of reproductive age undergoing F-18 FDG PET.
• Obtaining a detailed menstrual history is essential for accurate interpretation.
• Correlating PET findings with cross-sectional imaging (e.g., CT, MRI) can help exclude physiological causes and prevent false-positive diagnoses.