to occur in the ovary usually, rarely in the testis. Due to its rarity, the malignant potential of this tumour is unclear; there is one case report of late metastasis. Sex cord tumour with annular tubules, abbreviated SCTAT. These are rare tumours that may be sporadic or associated with Peutz–Jeghers syndrome. Diagnosis Definitive diagnosis of these tumours is based on the histology of tissue obtained in a biopsy or surgical resection. In a retrospective study of 72 cases in children and adolescents, the histology was important to prognosis. A number of molecules have been proposed as markers for this group of tumours. CD56 may be useful for distinguishing sex cord–stromal tumours from some other types of tumours, although it does not distinguish them from neuroendocrine tumours. Calretinin has also been suggested as a marker. For diagnosis of granulosa cell tumour, inhibin is under investigation. Granulosa cell tumors and Sertoli-Leydig cell tumors have specific genetic mutations that are characteristic and can help support the diagnosis. On magnetic resonance imaging, a fibroma may produce one of several imaging features that might be used in the future to identify this rare tumour prior to surgery. Prognosis A retrospective study of 83 women with sex cord–stromal tumours (73 with granulosa cell tumour and 10 with Sertoli-Leydig cell tumour), all diagnosed between 1975 and 2003, reported that survival was higher with age under 50, smaller tumour size, and absence of residual disease. The study found no effect of chemotherapy. A retrospective study of 67 children and adolescents reported some benefit of cisplatin-based chemotherapy. Research A prospective study of ovarian sex cord–stromal tumours in children and adolescents began enrolling participants in 2005. The International Ovarian and Testicular Stromal Tumor Registry is studying these rare tumors and collecting data on them to further research. Targeted treatments are being evaluated for these tumors as well. See also Sex cord Stroma of ovary References External links Gynaecological cancer Male genital neoplasia Ovarian cancer