FDG Uptake in Gestational Sac

A 39-year-old woman, with a newly diagnosed malignant melanoma of the right calf had negative CT scans of chest, abdomen, and thighs. Two weeks later, a whole body F-18 FDG PET scan showed a focal area of markedly increased metabolic activity in the left side of the pelvis, above and slightly posterior to the urinary bladder. A week later, ultrasound showed a well formed 5-week-old gestational sac in the left side of the uterus. The patient had a 10-year history of birth control pill use and reported she had menstrual bleeding a week before a CT scan.