Rare and uncommon tumours of the female pelvis: what the radiologist should know

Gynaecological tumours present a broad spectrum of histological subtypes due to the diverse anatomical and tissue origin of the reproductive organs. Rare tumours affect less than 6 per 100,000 individuals annually, posing significant challenges in diagnosis and management due to limited clinical awareness. Indeed, treatment protocols rely on options developed for more common histotypes, which may have limited efficacy on these rare tumours. In recent years, collaborative international efforts have started to address these gaps, improving standards of care. A comprehensive understanding of rare tumours' clinical and imaging features is necessary for radiologists in order to provide clinicians with useful information for treatment planning. In this review, we adopted an organ-based outline, describing rare tumours of the uterine corpus (leiomyosarcoma, endometrial stromal sarcoma, carcinosarcoma), cervix (gastric-type adenocarcinoma), and ovary (cystadenofibroma, lipid-poor teratoma, struma ovarii, immature teratoma, dysgerminoma). Additionally, tumours occurring at multiple sites, including lymphoma, neuroendocrine tumours, and aggressive angiomyxoma, are discussed. The objective is to help radiologists become familiar with these uncommon entities, ultimately increasing awareness on this topic.