FDG-PET-positive ovarian thecoma with GLUT5 expression: Five cases

Abstract

Positron emission tomography (PET) with fluorodeoxyglucose F18 (¹⁸ F-FDG) is useful for detecting malignancies, but benign lesions occasionally have false-positive ¹⁸ F-FDG uptake. Here, we report the cases of five postmenopausal women with solid ovarian tumors suspected to be ovarian cancer on magnetic resonance imaging and ¹⁸ F-FDG uptake. Mean age of the five patients was 57 years (range, 53-65 years). Average early standardized uptake value (SUV) of ¹⁸ F-FDG was 5.76 (range, 2.2-12.0) and delayed SUV was 6.56 (range, 2.4-13.8). In all five patients, frozen section diagnosis at surgery was thecoma, and bilateral salpingo-oophorectomy was performed. On immunohistochemistry, immunoreactive glucose transporter 5 (GLUT5) expression was detected in thecoma tissues. This case shows that thecoma sometimes has positive ¹⁸ F-FDG uptake on positron emission tomography-computed tomography (PET-CT), indicating the need for caution regarding false-positive PET-CT in patients with benign solid ovarian tumor.

Keywords: glucose transporter 5; positron emission tomography-computed tomography; thecoma.