Introduction: Ovarian cancer is a common malignancy in Indian women and it ranks third in women globally.Germ cell tumours are a group of ovarian tumours affecting young age that respond very well to chemo and radiotherapy.Tumors that are positive for CD117 marker have treatment in the form of imatinib. Present study was done to look at the rate of positivity of CD117 in malignant germ cell tumors and especially dysgerminomas.

Aim of the study: To study the histo–morphological features of ovarian tumors with emphasis on germ cell tumours including tumour size, macroscopic appearance, histological type, grade, stage and to study the immunohistochemical expression of CD117 in germ celltumours of ovary, particularly in dysgerminomas.

Materials and methods: This was a prospective study done in the Institute of Pathology and Electron Microscopy,Madras Medical College and Rajiv Gandhi Government General Hospital, Chennai,over a five year nine months period.The ovarian tumors were studied for light microscopy. Immunohistochemistry for CD117 was done in malignant germ cell tumors and it was correlated for patient age, histologic type, grade and stage of tumor.

Results: Surface epithelial tumors (75.5%) were most common followed by germ cell tumors(GCT) (16.5%).In the malignant GCT, 11 (36.6%) were dysgerminomas.The mean age for malignant GCT was 22.4 yearsand the average size was 15.7 cm.The immunohistochemicalexpression of C–kit was more in pure dysgerminoma (90.9%) than other malignant GCT but the correlation was not statistically significant.