Risk of Upstaging Due to Oncofertility Treatment Mimicking Pelvic Lymphoma on 18F-FDG PET/CT.

ABSTRACT A 23-year-old woman with primary mediastinal large B-cell lymphoma was referred to 18F-FDG PET/CT for staging. Besides the large mediastinal FDG-avid tumor, another FDG-avid lesion with an SUV higher than expected in corpus luteum cysts was found in the pelvis, raising suspicion for tumor. However, gynecologic ultrasound and review of patient chart revealed history of oncofertility treatment with GNRH analog. This prior treatment was responsible for the intense 18F-FDG uptake within the left ovary, way above the SUV levels commonly associated with menstrual cycle. In this case, the disease was downgraded to stage II, resulting in a less aggressive treatment.