Sex cord-stromal tumours of the ovary: a review highlighting recent advances

Ovarian sex cord-stromal tumours are uncommon tumours and as a group comprise only approximately 8% of ovarian neoplasms, at least half of which are accounted for by the relatively commonly encountered benign fibroma. However, even less commonly encountered tumours, such as those in the granulosa and Sertoli-Leydig groups, enter into the differential of a great range of generally more common tumours. Accordingly, some reasonable awareness of the features of these uncommon tumours is crucial in overall ovarian tumour diagnosis. Although these tumours may be functioning, tumours that may mimic them may also be functioning and may present a misleading clinical background to the pathologist. This review discusses the morphology of these tumours, highlighting their characteristic and some less known morphological features, updates the reader on some newly described features such as the occurrence of pseudopapillae in some granulosa cell tumours and endometrioid-like tubules in occasional Sertoli-Leydig cell tumours, and draws attention to a newly described entity, the microcystic stromal tumour. Other issues considered in the recent literature, such as re-exploration of the topic of cellularity and mitotic activity in fibroblastic neoplasms, are also considered. Although touched upon briefly, immunohistochemistry is not considered in detail as it is reviewed elsewhere in this mini-symposium.