Dysgerminoma Dysgerminoma corresponds to the seminoma of the testis and accounts for 3-5% of all ovarian tumours. It usually arises in young women or in children, with an average incidence at the age of 20. The tumour is solid with a peculiar elastic rubbery consistency and a smooth, firm capsule. The cut surface is yellow or grey with areas of degeneration and haemorrhage. The size is variable, usually moderate, though large tumours have been described. It is usually unilateral, bilateral in 10%, occasionally undergoes torsion and may, like all solid tumours, be associated with ascites. The tumour consists of large cells arranged in bunches or alveoli. Lymphocytes and giant cells are always found amongst the tumour cells. This appearance of large dark-staining nuclei with clear, almost translucent, cytoplasm and lymphocytic infiltration of the fibrous septa is diagnostic. The tumour is neutral and does not secrete either male or female sex hormones but placental alkaline phosphatase (PLAP), lactate dehydrogenase (LDH) and b-hCG. A number of patients with a dysgerminoma of the ovary have been repoed to show genital abnormality, with hypoplasia or absence of some pa of the genital tract. The malignancy rate is 30-50% and depends largely on the findings at laparotomy A unilateral tumour confined to one ovary is relatively benign. The presence of active invasion of the pelvic viscera is of poor prognosis. The presence of extra pelvic metastases in the general peritoneal cavity, lymph glands, omentum or liver renders the outlook hopeless. Reference : Shaw's Textbook of gynaecology 16th edition, pg no: 441 Dysgerminoma and granulosa cell tumours are highly radiosensitive