Stromal tumours of the ovary: an update

Stromal tumours of the ovary are reviewed emphasizing recently described entities and new or uncommon aspects of well known neoplasms. The first, the luteinized thecoma with sclerosing peritonitis, a rare lesion, is controversial with regard to whether it is neoplastic or non-neoplastic an unsettled issue. It often occurs in the young and has distinctive pathologic features. The second, the microcystic stromal tumour has as a main histologic feature the presence of microcysts that may only be focal. Hyaline plaques are common but in contrast to most stromal tumours they are inhibin and calretinin negative but show β-catenin alterations. Sclerosing stromal tumour although having relatively uniform typical morphology, can pose some diagnostic difficulty, especially when seen in pregnant patients. Thecoma and fibroma are the most common stromal tumours but thecoma, in particular, may cause diagnostic difficulty particularly with granulosa cell tumour. Finally, two rare tumours, the signet-ring stromal tumour and myxoma are briefly considered.