Tumour of an ovary - most often there are serous, mucinous tumours of an ovary. The serous tumour develops usually from a cystoma, is characterized by accumulation of a serous liquid inside of cystic formations. At germination of a capsule and an innidiation the ascites is formed. The mucinous tumour is shown by development of the tumoral formations containing slime; at break the pseudomyxoma of a peritoneum develops in an abdominal cavity. The serous tumour meets more often in the age of 40-60 years, mucinous - after 60 years. In 40-70 % of cases the malignant tumour amazes both of an ovary. The innidiation of the specified forms of a tumour of an ovary occurs in an abdominal cavity (on a peritoneum, in an omentum). The metastatic ascites, a pleuritis can develop. Rather seldom there are metastasises in a liver, easy, other organs. The recurrent tumor of an ovary is more often localized in the field of a small basin.