Characteristics of Ovarian Metastases on F-18 FDG PET/CT

PurposeThe aim of this study is to determine the morphological and metabolic parameters of ovarian metastases on F-18 FDG PET/CT that can further aid in differentiating secondary ovarian malignancy from the primary one.Materials and MethodsThis is a retrospective study approved by the institutional ethical committee. All the patients with known non ovarian malignancies who underwent F-18 FDG PET/CT from February 2021 to 2023 at Department of Nuclear Medicine in All India Institute of Medical Sciences, Jodhpur, India, were screened for ovarian metastases in view of abnormal increased FDG uptake in one or both the ovaries. The parameters of the ovarian metastases recorded were laterality, SUV max (g/ml), attenuation and presence or absence of non-ovarian distant metastatic sites.Results7 female patients met the inclusion criteria, and total of 11 ovarian lesions were recorded. The median age group of patients was 49 years (27-64 years). The ovarian metastases show moderate to intense FDG uptake and median SUV max (and inter-quartile range) was 7.5 (6.8) g/ml. The median volume of the ovarian metastases was 37.8 cubic cm, with range from 9 to 17.9 cubic cm. Breast was the most common primary malignant site (57%), followed by liver, colon and unknown primary-squamous cell carcinoma. Majority of the lesions were bilateral (57%), and only left ovary was involved in the unilateral lesions. None of the metastases was observed in right ovary alone. Variable attenuation patterns were observed of which majority were solid (44%) in nature, followed by predominantly cystic (28%) and mixed (28%). 100% of the patients had imaging evidence of non-ovarian distant metastases at the time of diagnosis.ConclusionOvaries are a rare site of metastases, usually bilateral in presentation and commonly involves left more than right ovary. They show moderate to intense FDG uptake and present variable attenuation patterns with most of them being solid in nature and rest of them are either predominantly cystic or mixed in attenuation. They are strongly associated with distant non-ovarian metastases at the time of diagnosis ovarian metastases suggesting poor prognosis.