The Swyer syndrome, 46, XY gonadal dysgenesis, belongs to the category of sexual abnormality [2
]. The syndrome was complete/pure gonadal dysgenesis. The patients with 46, XY gonadal dysgenesis are diagnosed in early adolescence with delayed pubertal development. The patients' mesonephric ducts (Wolffian ducts) are in atrophy, paramesonephric ducts (Müllerian ducts) develops to uterus, fallopian tubes and part of the vagina as a result of lacking testosterone and inhibitor of Müllerian ducts. As expected they show elevated gonadotropins, normal female levels of androgens, low levels of estrogens, female external genitalia, uterus and fallopian tubes. Minimal breast enlargement reflects peripheral aromatization of androgens. Both gonads display fibrous tissue that vaguely resembles ovarian stroma but no follicles. The etiology of 46, XY pure gonad dysgenesis is thought to be a shot arm Y chromosome deletion involving SRY (putative testicular-determining factor gene), a mutation in other genes that leads to inhibition of SRY function or mutation of SRY function [3
Swyer syndrome should be differentiated from the following two female phenotype (karyotype XY) syndrome. One is the familial syndrome of testicular feminization, the most common type of male pseudohermaphroditism. It occurs in individuals with a normal male chromosome constitution with an end-organ defect (androgen insensibility). It characterized by the presence of several well-developed female secondary sex characteristics. Individuals are found to have a vagina (not a true vagina, but like a small "cupule"), bilateral cryptorchid testes but no uterus [4
]. The other is true hermaphrodites, which may have ovotestes containing both ova and immature seminiferous tubules or other combinations of ovary and testis [6
In patients with gonadal dysgenesis, either "pure"(with a 46,XX or 46, XY karyotype) or associated with the somatic features of Turner's syndrome (with a 45,XO karyotype), both gonads are represented by a streak of fibrous tissue that vaguely resembles ovarian stroma [8
]. Previously thought these patients do not seem to have an increased incidence of gonadal tumors [10
]. But modern studies show patients with 46, XY pure gonadal dysgenesis are at a higher risk of developing gonadoblastoma and dysgerminoma, and may occur even in young ages. The incidence of Swyer syndrome is 1:100 000 [11
]. A bilateral gonadectomy should be done especially by laparoscopy when a Swyer syndrome is discovered in order to avoid the risk of malignant transformation. There is possibility of pregnancy by oocyte donation in some countries if the uterus was not removed for a malignant etiology.
In this report, we provide a case of dysgerminoma diagnosed in a dysgenetic gonad of a 21-year-old patient with Swyer syndrome, who presented with primary amenorrhea and infertility of five years duration. Karyotype was consistent with 46, XY (pure). In our case, testosterone free was 34.5 pmol/L, sex hormone binding globulin was 16.50 nmol/L, and menstrual function was associated with estradiol valerate and medroxyprogesterone prescribed by doctor. Estrogen and progestin sequential therapy supports female secondary sex development in patients with gonadal dysgenesis. The patient did not have a bilateral gonadectomy after knowing she has a 46, XY caryotype because she wanted to be pregnant and did not believe she had the risk of suffering from malignent of ovary. It is necessary to take the familial screening of Swyer syndrome cases. As a malignant germ cell tumor of the ovary, dysgerminoma can be found either in a pure form or mixed with other germinal elements. Therefore in premenarchal patients with a pelvic mass, the karyotype should be determined.
Differential diagnosis for dysgerminoma include diffuse large B cell lymphoma, poorly differentiated carcinoma, embryonal carcinoma and gonadoblastoma. Coexistence of dysgerminoma and gonadoblastoma is seen in about 50% of cases [13
]. Histologic appearance of gonadoblastoma may be altered by hyalinization, calcification, and/or overgrowth of a malignant germ cell element predominantly dysgerminoma. Maleki et al. reported a case of dysgerminoma and gonadoblastoma in a dysgenetic gonad on a touch preparation that described cytomorphologic findings of both neoplasms [14
About 65% of dysgerminomas are stage I at diagnosis. About 85 ~ 90% of stage I tumors are confined to one ovary; 10 ~ 15% are bilateral. Dysgerminoma is the only germ cell malignancy that has this significant rate of bilaterality, other germ cell tumors being rarely bilateral. The treatment of patient with early disgerminoma is resection of the primary lesion and proper surgical staging. Chemotherapy and/or radiotherapy are administered to patients with metastases. In patients whose contralateral ovary has been preserved, some disease can develop in 5 ~ 10% of the retained gonads over the next 2 years [15