Benign Tumours of the Ovary

Structure of ovaries:
The ovaries are covered on the outside by a layer of simple cuboidal epithelium called germinal (ovarian) epithelium. This is actually the visceral peritoneum that envelops the ovaries. Underneath this layer there is a dense connective tissue capsule, the tunica albuginea. The substance of the ovaries is distinctly divided into an outer cortex and an inner medulla. The cortex appears more dense and granular due to the presence of numerous ovarian follicles in various stages of development. Each of the follicles contains an oocyte, a female germ cell. The medulla is loose connective tissue with abundant blood vessels, lymphatic vessels, and nerve fibers.


Ovarian cysts may be physiological or pathological & may arise from any tissue in the ovary.

Pathology:
Physiological cysts:
Physiological cysts are simply large versions of cysts which form in the ovary during the normal ovarian cycle. Most are asymptomatic incidental findings at pelvic examination or ultrasound scan. They are an occasional complication of ovulation induction, also may occur in premature female infants & in women with trophoblastic disease.

Follicular cyst:
It results from non-rupture of a dominant follicle or failure of atresia in a non-dominant follicle. A follicular cyst may persist for several menstrual cycles & may achieve a diameter of up to 10 cm. intervention may be required if symptoms develop or if the cyst does not resolve after 8-16 weeks. They may produce estrogen causing menstrual disturbance & endometrial hyperplasia.

Luteal cyst:
Less common than follicular cyst, they are more likely to present with intraperitoneal bleeding, commonly on the right side due to increased intraluminal pressure secondary to ovarian vein anatomy. Corpora lutea are not called luteal cyst unless they are more than 3 cm.