Ovarian cysts: types

Benign ovarian cysts are extremely common. They may be divided into physiological cysts, benign germ cell tumours, benign epithelial tumours and benign sex cord stromal tumours.

Complex (i.e. multi-loculated) ovarian cysts should be biopsied to exclude malignancy.

Physiological cysts (functional cysts)

Follicular cysts

• commonest type of ovarian cyst
• due to non-rupture of the dominant follicle or failure of atresia in a non-dominant follicle
• commonly regress after several menstrual cycles

Corpus luteum cyst

• during the menstrual cycle if pregnancy doesn't occur the corpus luteum usually breaks down and disappears. If this doesn't occur the corpus luteum may fill with blood or fluid and form a corpus luteal cyst
• more likely to present with intraperitoneal bleeding than follicular cysts

Benign germ cell tumours

Dermoid cyst

• also called mature cystic teratomas. Usually lined with epithelial tissue and hence may contain skin appendages, hair and teeth
• most common benign ovarian tumour in woman under the age of 30 years
• median age of diagnosis is 30 years old
• bilateral in 10-20%
• usually asymptomatic. Torsion is more likely than with other ovarian tumours

Benign epithelial tumours

Arise from the ovarian surface epithelium