Ovarian granulosa cell tumours are relatively uncommon sex-cord–stromal neoplasms that account for approximately 1–2% of all ovarian malignancies. They are of adult or juvenile type, the former being more common. The prognosis of juvenile granulosa cell tumour (JGCT) is excellent, with tumour recurrence or metastasis being rare, although when this neoplasm does recur, this is usually early.1 Adult granulosa cell tumour (AGCT), on the other hand, is regarded as a low-grade malignant neoplasm since there is a significant propensity for recurrence or metastasis. Often the recurrent or metastatic tumour manifests itself many years after removal of the primary neoplasm with intervals in excess of 10 or even 20 years being not uncommon; the longest reported period from initial removal to tumour recurrence is 37 years.2 The 10-year survival for AGCT has been variously reported as between 60 and 90%; however, the 25-year survival is significantly lower and in the region of 40–60%.3 Most AGCTs are confined to the ovary at diagnosis, that is stage I, and the overall 10-year survival for these is in the region of 85–95%. In most institutions, stage I AGCTs are not given adjuvant therapy and, as such, it would be important to identify prognostic factors that might predict those stage I tumours that are likely to recur since patients could be advised on the likelihood of recurrence, and those with neoplasms with adverse features might be offered adjuvant therapy following surgical removal. Multiple studies have investigated whether there are features that predict which stage I AGCTS are likely to recur and the paper by Leuverink et al in this issue examines the value of mitotic indices and Ki-67 proliferation index in this regard.4 We critically review the published literature in an attempt to ascertain whether there are any clinicopathological features that …