malignant neoplasm ovary - Dysgerminoma

Germ cell tumours constitute about 15-20 per cent of all ovarian neoplasm and they are the second common ovarian tumours. For classification see p. 281. They have got varying degrees of malignant potentiality. About 3 per cent of these tumours are malignant. Germ cell tumours occur predominantly in children and young adults. They arise from embryonic germ cells.

Dysgerminoma

                       Dysgerminoma is the commonest (30-40%) malignant germ cell tumour. It arises from undifferentiated form of germ cells. It is often (5%) associated with dysgenetic gonad (see Ch. 27). The counter part of dysgerminoma in male is seminoma. ‘Majority (75%) of the tumours occur before the age of 30 years.

hCG assays are often positive, confusing the diagnosis with pregnancy. It may coexist with pregnancy (20-30%). Dysgerminoma may be associated with choriocarcinoma or endodermal sinus tumour. Tumour markers a-fetoprotein (AFP) and hCG may be positive in that situation. Karyotyping is needed specially when a premenarcheal girl presents with a pelvic mass.

Pathology: The shape is usually round or oval and is usually 5-15 cm in diameter; feel is boggy, at times it is firm rubbery. It may be bilateral (10%). Cut section shows pink or yellow colour. Microscopic appearance reveals uniform large round cells (monotonous pattern), arranged in cords or clumps with abundant clear cytoplasm. Nuclei are large, irregular and hyperchromatic with varying degree of mitosis. There is intense infiltration of lympho~ Cytes and plasma cells in the fibrous septum (Fig. 23.25). In more than 50 per cent, they are potentially malignant.

Clinical features are not specific for the tumour.

Treatment: Majority (75%) of dysgerminomas are Confined to one ovary and are stage I at the time of diagnosis.

In a young patient where preservation of fertility is desired, laparotomy for surgical staging and unilateral salpingo-oophorectomy’ is' done. If there is any suspicion of involvement to the other ovary, bisection of the contralateral ovary, and excisional biopsy should be done. The tumour is sensitive to both chemotherapy and radiotherpy