Non-Neoplastic Functional Disorders: Functional Cysts
The development of simple cysts is quite common in adolescents, and the risk of malignancy is close to zero. In the pubertal period, ovaries may contain multiple follicles in different stages of development, and most simple cysts result from the failure of maturing follicles to ovulate and involute. This cystic transformation may be due to either inadequate or excessive ovarian stimulation, as indicated by increased frequency in the pubertal or perimenopausal periods, after treatment to induce ovulation or during treatment with certain microdose progestative contraceptive pills.

The frequency of functional cysts is most certainly underestimated as asymptomatic and spontaneously regressive forms go unrecognized. In a series of 139 observations of adolescent girls who had undergone routine ultrasonography, 12% of the girls had cysts that resolved spontaneously within 3 months. Management depends on clinical symptoms and the diameter and appearance of the cyst. Mere surveillance is only decided if the cyst is a simple one and, inversely, surgery is called for if lesions are suspect and their histological nature must be determined.

When the cyst is unilateral and purely fluid on ultrasonography, surveillance for 3 months with a monthly ultrasound check-up is indicated. Treatment with progestogens or a combined oral contraceptive reduces the time the cyst takes to resolve and decreases the risk of recurrence. In a series of 144 patients, cysts resolved in 3 weeks with estroprogestative treatment compared with 4.5 weeks without treatment. The adolescent should be informed that ultrasonography must be done if acute pain develops, because of the risk of adnexal torsion. If the cyst persists after 3 months or if it rapidly increases in volume, surgery by laparoscopy or laparotomy may be necessary to remove the cyst for histopathological study. This makes it possible to differentiate a simple cyst from a paraovarian or paratubal cyst, a hydrosalpinx or certain epithelial tumors such as serous cystadenomas. These simple cystic processes are not neoplasms and are considered as physiological variations; they are benign and derived from a follicule (first part of the cycle), a corpus luteus (after ovulation) or the cells of the internal theca.

Epidemiology: Predisposing Factors
In the adolescent girl, risk factors such as early menarche, long menstrual cycles or oligomenorrhea may increase the possibility of ovarian cyst. Inversely, the risk decreases if the first menses appeared after the age of 14 years (odds ratio (OR) 0.4), cycles are short and regular (<26 days), and the patient is obese (OR 0.5). The risk is, however, doubled with irregular menses (OR 1.9).

Risk may be affected by tobacco consumption, with a twofold relative increase of risk in patients who are smokers.

Special Etiology
Rare cases of aromatase gene mutation have been described in 46,XX girls with primary amenorrhea, bilateral ovarian cysts and impuberism, contrasting with increasing virilization. Aromatase is the enzyme that catalyzes the hydroxylation involved in the conversion of androgens into estrogens.

The aromatase deficiency of these girls accounts for their hypergonadotrophic hypogonadism, high androgen levels and macropolycystic ovaries. Estrogen treatment results in feminization, menstruation and ovarian cyst regression.

Endometriosis
Endometriosis is characterized by the presence of endometrial tissue outside the uterine cavity. It is rare during puberty and is marked by dysmenorrhea with a large endometrial cyst located in the adnexal fallopian tube or in the ovary, the so-called endometrioma or chocolate cyst. Ultrasonography and MRI may be helpful in identifying an ovarian endometrioma, which is more easily recognizable during the menses. At the onset of disease, surgery is necessary and includes resection of the cyst wall of the endometrioma. Medical treatment can be considered at a later stage.

Several complementary theories have been advanced to explain this disorder: the first is the theory of tubal reflux described by Sampson in 1925. In vaginal aplasia in the syndrome of Rokitansky-Kuster-Mayer-Hauser, ovarian endometrioid nodules are observed earlier and more frequently.

A second more recent theory to account for the hypofertility of these patients is that it is caused by a significant decrease in the physiological apoptosis of the endometrial cells. Numerous factors of immunological disturbance, such as fibronectin, interleukins and insulin-like growth factor, seem to play an important role. A Canadian study has stressed the predisposing role of factors such as short cycles, menses lasting more than 5 days, excess weight and above-normal alcohol and caffeine consumption.

Benign and Malignant Neoplastic Disorders
The WHO has published a classification of ovarian tumors based on histologic cell type and benign versus malignant nature. This classification is shown in

table 2. Staging of malignant ovarian tumors has been defined by the International Federation of Gynecology and Obstetrics (FIGO) (

table 3).

Ovarian neoplasms occur in 2 - 25% of adnexal masses in adolescent series. Germ cell tumors are the most common tumors and represent 50 - 60% of ovarian tumors in women aged under 20. About 95% of these tumors are benign cystic teratomas and 5% are mixed malignant germ cell tumors with several histological components secreting various tumor markers, β-hCG or αFP.

Common epithelial tumors increase in frequency in the second decade, from 16% before 14 years to 28% at 17 years. Serous cystadenomas seem the most common (50% of cases) and the incidence of borderline tumors increases with age. Sex cord-stromal tumors consist of epithelial (granulosa- Sertoli cells) and mesenchymal elements in a variety of combinations.

Granulosa cell tumors are the most frequent feminizing tumors and the juvenile form is of low malignant potential.