A tale of 3 tracers : contrasting uptake patterns of 18F-fluciclovine, 68Ga-PSMA, and 18F-FDG in the uterus and adnexa

Abstract

A 41-year-old woman with newly diagnosed invasive lobular carcinoma of the breast underwent sequential 68Ga-PSMA-11 PET/CT and 18F-fluciclovine PET/CT as part of an ongoing clinical trial (NCT04750473). 68Ga-PSMA PET/CT showed increased radiotracer uptake in the uterine endometrium and left adnexa. 18F-fluciclovine PET/CT showed increased radiotracer uptake in an enlarged uterus in a known uterine leiomyoma. A clinical 18F-FDG PET/CT demonstrated radiotracer uptake in the endometrium and a circumferential area of uptake in the left adnexa, a pattern more similar to the 68Ga-PSMA uptake pattern. This case highlights the discordance in the uptake pattern of two radiotracers in different benign gynecological conditions. While these tracers are approved for prostate cancer imaging, they are increasingly being used in other malignancies.