Cystic adnexal lesions

The fallopian tubes are paired tubular structures, approximately 10 cm in length extending from the uterus to the ovaries.

The fallopian tubes consist of four parts. From medial to lateral, these are the isthmus, ampulla, infundibulum, and fimbriae. The fimbrial segments overhang the ovary and communicate with the peritoneal cavity.

The fallopian tubes are contained within two folds of the broad ligament.

The ovaries lie within the lateral pelvic sidewalls in the ovarian fossae. Normal ovaries are paired ovoid structures, roughly measuring 4 × 3 × 2 cm, although their volume varies with age, menopausal status, and menstrual cycle.

The ovary is surrounded by an outer fibrous layer of tunica albuginea. Its internal structure is comprised of three zones—an outer cortex, inner medulla and a hilum. The cortex contains follicles, corpus lutea, fibroblasts, and smooth muscle cells.

The ovary has two functions: hormone production and oocyte production (folliculogenesis). Oocyte precursors present from birth are known as primordial germ cells. Following puberty, these mature under the influence of follicle stimulating hormone and luteinizing hormone. In each cycle, approximately 20 follicles are activated, with usually just one follicle fully maturing, while the others contribute to endocrine function.

On magnetic resonance imaging (MRI), ovaries are recognized as ovoid structures containing T2 hyperintense physiologic follicles with intervening T1 hypointense stroma ( Fig. 33.1 ).

On computed tomography (CT), they have soft tissue attenuation and may contain a follicle or corpus luteal cyst.

The broad ligament is a sheet of peritoneum that extends from the uterine body to the lateral pelvic walls and has three components: mesometrium, mesovarium, and mesosalpinx.

The caudal extent of the broad ligament is defined by the cardinal ligaments.

The broad ligament is usually not visible on imaging unless there is pelvic ascites.

The broad ligament contains the ovarian ligament, round ligament of the uterus and suspensory ligament of the ovary.

The ovaries have a dual arterial blood supply. The main arterial supply comes from the ovarian artery, a branch of the abdominal aorta arising at the L2 vertebral level. Collateral supply comes from the ovarian branches of the uterine artery.

The ovarian vein is typically single, but may also be multiple and accompanies the ovarian artery. The left ovarian vein drains into the left renal vein, and the right ovarian vein drains into the inferior vena cava. The ovarian lymphatics drain into the paraaortic lymph nodes at the level of the lower pole of the kidneys.