Ovary, Sclerosing stromal tumour, inhibin stain

Sclerosing stromal tumour (SST) of the ovary, which occurs mostly in young women, is a rare benign stromal tumour. Electron microscopy has shown that the cells in SST are a mixture of luteinized theca-like cells, spindle-shaped fibroblastic cells and primitive mesenchymal cells. The histologic features are of cellular clusters of mixed spindled and rounded cells, set within a hypocellular fibrous to myxoid stroma with thin-walled vessels. Cells in the cellular areas are positive for inhibin, calretinin, smooth muscle actin, CD10, ER, PR and vimentin.

The differential diagnosis for this tumour includes fibroma, thecoma, and metastatic signet ring cell carcinoma (Krukenberg tumour).The prognosis is excellent based on the limited number of cases reported in the literature.

This slide shows inhibin stain. See related content for H&E stain.