Dysgerminomas are one of the germ cell tumour ovarian neoplasms. They are the most common malignant germ cell ovarian carcinoma. Most dysgerminomas occur in adolescence and early adult life; 5% occur in pre-pubertal children, and they are extremely rare after age 50.

Abnormal gonads (due to gonadal dysgenesis and androgen insensitivity syndrome) have a high risk of developing a dysgerminoma. Most dysgerminomas are associated with elevated serum lactic dehydrogenase (LDH), which is sometimes used as a tumour marker. Dysgerminomas present as bilateral tumours in 10% of patients and, in a further 10%, there is microscopic tumour in the other ovary.

On gross examination, they have a smooth, bosselated external surface, which is soft, fleshy and cream-coloured, gray, pink or tan when cut. Microscopic examination reveals uniform cells that resemble primordial germ cells.

Typically, the stroma contains lymphocytes and 20% have sarcoid-like granulomas. Metastases are most often lymphatic, and dysgerminomas are very sensitive to chemotherapy and radiotherapy, making prognosis excellent.

Dysgerminomas can be located in the brain, usually arising in the hypothalamic or epiphysial regions.