Swyer syndrome (pure gonadal dysgenesis, XY) represents a rare form of disorder of sexual development that was first described by Jim Swyer in 1955 [4]. It has an incidence of about 1:80,000 [2]. The etiology of Swyer syndrome is thought to be due to genetic mutation of genes required for testicular formation. It is usually caused by a mutation in the SRY gene due to deletion in the DNA-binding region of the SRY gene. But it may be due to mutation in other genes that leads to inhibition of SRY function or mutation of SRY function [6, 7].
Swyer syndrome is usually presented at the time of puberty and adolescence with primary amenorrhea. This syndrome is characterized by phenotypically female with female external genitalia, gonadal dysgenesis with bilateral streak gonads and Mullerian structures (small or rudimentary uterus, fallopian tube, vagina). On karyotyping, 46XY is detected [2, 5, 8].
The differential diagnosis of Swyer syndrome (Pure gonadal dysgenesis, XY) includes Mayer–Rokitansky–Küster–Hauser syndrome (XX), which is a common cause of primary amenorrhea [2]. This syndrome has an incidence of one in every 5000 live females [9]. It is characterized by variable degrees of Müllerian duct aplasia with aplasia of the vagina and a rudimentary or absent uterus. But on the contrary to Swyer syndrome, they have normal secondary sex characteristics and a normal female karyotype (46, XX) [9, 10].
Swyer syndrome has another differential diagnosis: Congenital Androgenic Insensitivity Syndrome. In Congenital Androgenic Insensitivity Syndrome, the karyotype is XY with high testosterone level. These patients have a female phenotype with normal, yet undescended testis present, absent Mullerian structures and normal breast development [4, 11]. On the other hand, the breasts are usually underdeveloped with low testosterone levels in Swyer syndrome as in our case.
Also, because true hermaphrodites can present with a female phenotype, they are a differential diagnosis for Swyer syndrome. True hermaphrodite patients, on the other hand, may have ovotestes or a combination of an ovary and testes [6].
Because of the presence of the Y chromosome, patients with pure gonadal dysgenesis XY are at a higher risk of developing germ cell neoplasms. Gonadoblastoma and dysgerminoma are the most common [6, 8]. As a result, in Swyer syndrome, bilateral prophylactic gonadectomy is considered to reduce the risk of developing germ cell neoplasm [6].
Gonadoblastoma is an uncommon germ cell-sex cord-stromal tumor. They are associated with disorders of sexual development. Gonadoblastoma is a mixed germ cell tumor with undifferentiated cells. This makes it a precursor to seminoma/dysgerminoma tumors [12]. The gonadoblastomas are associated with dysgerminoma in 50–60% of cases and with other malignant germ cell tumors like yolk sac tumor, embryonal carcinoma, and choriocarcinoma in 10% of cases [13].
Dysgerminoma is a malignant tumor that arises from the primordial germ cells identical to testicular seminoma [5, 12]. Imaging findings of Dysgerminoma include multilobulated solid masses with prominent fibrovascular septa and speckled calcifications [5, 14].
In our case CT confirms the presence of calcification that was suspected in the ultrasound. Raafey et al. described a case of bilateral gonadoblastoma with dysgerminoma that was manifested by bilateral adnexal lesions with calcifications [15].