Tumours of the Ovary

Abstract

These include the following:

• 1. Mucinous cystadenoma: large, multilocular, unilateral cysts with mucinous contents, lined by a single layer of columnar cells. Papillary processes are rare and suggest malignancy. Malignant change is present in 5–10% of cases of mucinous cystadenocarcinoma. A rare complication is pseudomyxoma peritonei in which the cells implant throughout the peritoneum and continue to secrete mucin.

• 2. Serous cystadenoma: the incidence is one quarter that of mucinous cystadenomas. They are smaller than mucinous lesions, bilateral in 50% of cases, often unilocular, and lined by cubical or columnar epithelium (sometimes ciliated). Papillary processes are common but are likely to be malignant only if they penetrate the capsule. The stroma may contain small calcium deposits (“psammoma bodies”).

• 3. Dermoid cysts: these are the commonest neoplastic cysts in young women but may be found at any time of life. They are usually less than 12 cm in diameter; 10% are bilateral. Cysts lying in the pouch of Douglas or anterior to the uterus are usually dermoids. The contents are thick and yellow. The main constituent is skin and associated structures (hair, sebaceous and sweat glands, and teeth) but a variety of other tissues may be found (alimentary and respiratory epithelium); functional thyroid tissue (struma ovarii); neural tissue (cartilage and bone); very rarely, there may be partial embryo formation (fetus in fetu). Solid teratomata may be benign but are more commonly malignant. Primary choriocarcinoma, melanoma and carcinoid can occur. Unlike gastrointestinal argentaffinomas, ovarian carcinoid may cause systemic effects prior to metastasis because the serotonin is not destroyed in the enterohepatic circulation.

• 4. Fibroma: these are rare, lobulated tumours, bilateral in 10% of cases. They often produce ascites and occasionally a right-sided pleural effusion (Meig’s syndrome). They may be difficult to distinguish macro-and microscopically from theca cell tumours.