Uterine tumour resembling ovarian sex cord tumour: first report of a large series with follow-up

Aims: Uterine tumour resembling ovarian sex cord tumour (UTROSCT) is an uncommon mesenchymal neoplasm of uncertain histogenesis. While it is considered a neoplasm of uncertain but low malignant potential, there is limited evidence for this as there are no large studies with follow-up. We aimed to determine the clinical behaviour of this uncommon neoplasm and investigate clinicopathological parameters which predict behaviour. Methods and results: From a series of 34 cases of UTROSCT, mainly from consultation practice, we obtained follow-up information which was obtained by contacting referring pathologists and clinicians. The follow-up periods ranged from 6 to 135 months (mean 39 months). Eight of 34 patients (23.5%) developed extrauterine metastasis to a variety of sites, including pelvic and abdominal peritoneum, ovary, lymph nodes, bone, liver and lung, and three patients (8.8%) died of tumour. Those neoplasms which exhibited malignant behaviour occurred on average in older patients, and were larger and more likely to exhibit necrosis, lymphovascular invasion, cervical involvement, significant nuclear atypia and significant mitotic activity. However, only the presence of necrosis and significant mitotic activity was statistically significant. Conclusions: While our figure of 23.5% of cases exhibiting malignant behaviour may reflect some bias related to consultation practice our results show that, not uncommonly, these neoplasms have an aggressive clinical course with extrauterine metastasis. Given the overlap in pathological parameters between clinically benign and malignant neoplasms, UTROSCTs are all best regarded as potentially malignant.