Congenital Anomalies and Benign Conditions of the Ovaries and Fallopian Tubes

FUNCTIONAL AND BENIGN OVARIAN TUMORS

The human ovary has a striking propensity to develop a wide variety of tumors, most of which are benign. As indicated in Table 20-1, ovarian masses may be functional, inflammatory, metaplastic, or neoplastic. During the childbearing years, 70% of noninflammatory benign ovarian tumors are functional. The remainder are either neoplasms (20%) or endometriomas (10%). The management of ovarian tumors, whether functional, benign, or malignant, involves difficult decisions that may affect a woman’s hormonal status or her future fertility. Although only functional cysts and benign ovarian neoplasms are considered in detail in this chapter, diagnostic methods to differentiate benign masses from malignant ones are discussed.

TABLE 20-1 DIFFERENTIAL DIAGNOSIS OF OVARIAN MASSES

Functional Ovarian Cysts and Tumors

Dozens of ovarian follicles form the “cohort of follicles” of each menstrual cycle. To be classified a functional cyst, the follicle must reach a diameter of at least 3 cm. Functional cysts may cause pelvic pain, a dull sensation, or heaviness in the pelvis.

A follicular cyst, lined by one or more layers of granulosa cells, develops when an ovarian follicle fails to rupture. Similarly, a lutein cyst may develop if the corpus luteum becomes cystic, grows to larger than 3 cm, and fails to regress normally after 14 days. Hemorrhagic cysts, especially hemorrhagic corpus luteum cysts, are more likely to cause symptoms and are more vulnerable to rupture toward the end of the menstrual cycle. The hemorrhage within the cyst results from invasion of the ovarian vessels into the corpus luteum cyst 2 to 3 days after ovulation.

Other specific types of lutein cysts may occur with abnormally high serum levels of human chorionic gonadotropin (hCG) or increased ovarian sensitivity to gonadotropins. Theca-lutein cysts may develop in association with the high levels of hCG present in patients with a hydatidiform mole or choriocarcinoma. Patients undergoing ovulation induction with gonadotropins or clomiphene may also develop theca-lutein cysts. Theca-lutein cysts are usually bilateral, may become quite large (>30 cm), and characteristically regress slowly after the gonadotropin level falls. Rarely, when follicles are stimulated with gonadotropins, theca-lutein cysts can become so extensive as to cause massive ascites and dangerous problems with systemic fluid imbalance.

A luteoma of pregnancy is a related condition in which there is a hyperplasic reaction of ovarian theca cells, presumably from prolonged hCG stimulation during pregnancy. The luteomas characteristically appear as brown to reddish-brown nodules that may be cystic or solid. A luteoma of pregnancy (Figure 20-1) may be associated with multifetal pregnancies or hydramnios. They can cause maternal virilization in 30% of women and, less often, ambiguous genitalia in a female fetus. Although ovarian enlargement may be impressive, surgical resection is not indicated because luteomas regress spontaneously postpartum.

FIGURE 20-1 Gross appearance of a luteoma of pregnancy. Note the multiple brown nodules.

(From Voet RL: Color Atlas of Obstetric and Gynecologic Pathology. St. Louis, Mosby, 1997.)

Polycystic ovary syndrome, a functional disorder generally associated with chronic anovulation and hyperandrogenism, can also produce enlarged ovaries with multiple simple follicles (Figure 20-2). The hormonal aspects of this syndrome are discussed further in Chapter 32.

FIGURE 20-2 Ovary with multiple cysts lining the capsule consistent with polycystic ovary syndrome.

(Courtesy of Dr. Sathima Natarajan, Ronald Reagan–UCLA Medical Center.)

CLINICAL FEATURES

An ovarian follicular cyst is usually asymptomatic and unilocular (simple) and can reach 15 cm in diameter. It usually regresses during the subsequent menstrual cycles. In general, a lutein cyst is apt to be smaller but more firm or even solid in consistency and is more likely to cause pain or signs of peritoneal irritation. Because it may continue to produce progesterone, it is also more likely to cause delayed menses. On occasion, a functional ovarian cyst may undergo torsion (see later) or may rupture, which may produce acute lower abdominal pain and tenderness and significant hemoperitoneum.

DIAGNOSIS

The presumptive diagnosis of a functional ovarian tumor is usually made when a 5- to 8-cm cystic adnexal mass is noted on bimanual examination; it is confirmed when the lesion regresses over the course of the next several cycles. In general, a functional cyst is mobile, unilateral, and not associated with ascites. On rare occasions, the mass may exceed 8 cm and be quite tender to palpation. On occasion, hemorrhagic lutein cysts may have a solid rather than a cystic consistency. A pelvic ultrasound will confirm the cystic nature of the mass, but it cannot differentiate with certainty between a functional and a neoplastic tumor.

All suspicious adnexal masses in premenopausal and postmenopausal women must be carefully evaluated. Table 20-2 contains a useful risk assessment tool, the risk for malignancy index (RMI), which can be used to help identify those ovarian masses that could be malignant. The RMI has high sensitivity (87%) and specificity (97%).

TABLE 20-2 CALCULATION OF THE RISK OF MALIGNANCY INDEX^∗ FOR AN OVARIAN MASS

Criteria	Scoring System
A. MENOPAUSAL STATUS
Premenopausal	1
Postmenopausal	3
B. ULTRASONIC FEATURES
Multiloculated Solid areas Bilaterality Ascites

1 feature = 1

≥2 features = 3

C. SERUM CA-125 TITER Absolute value

∗ Risk of Malignancy Index = A × B × C. A cut-off value of 200 discriminates a benign from a malignant mass with a sensitivity of 87% and a specificity of 97%.

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