Case 76. Gonadoblastoma in a Dysgenetic Testis

Clinical case. A 6-month-old patient with bilateral cryptorchidism. On the left side, in the surgical exploration, a cord-like structure that was interpreted as a uterine tube was found attached to the testicle. This testicle and the tube were removed. The phenotype was male and the karyotype 46, XY.

Pathological findings. The testicle measures 1.2 × 1 × 1 cm. Macroscopically, it presents no alterations. Histologically, at the level of the upper pole it shows important changes in the albuginea and in the parenchyma. The albuginea is thin, poorly collagenized, but in its thickness it shows a tissue similar to that of ovarian stroma and seminiferous tubules. It does not present a good delimitation form testicular parenchyma. Immediately below the albuginea, there are many nodular and cordonal formations. Each nodule is constituted by two types of cells. Most of them are small, the largest ones are similar to gonocytes and are distributed irregularly throughout the tumor nodule. Between both types of cells there are eosinophilic bodies (Call-Exner bodies). Externally, each nodule is lined by a basement membrane and surrounded by fibrous tissue. The small cells are positive for inhibin and the larger ones for PLAP and OCT3/4. The seminiferous tubules of the rest of the parenchyma have marked a decrease in germ cell number. The delineation between the tumor and the residual parenchyma is poor.

Comments. The gonad has two features of interest. First, it meets the characteristics of a dysgenetic testicle; second, it is a carrier of a gonadoblastoma. The dysgenetic testicle is defined by the presence of three findings: thin and poorly collagenized albuginea, absence of separation plane of the albuginea and testicular parenchyma, and the presence of seminiferous tubules inside. As the normal collagenization of the albuginea is dependent on AMH, the abnormal thickness and collagenization of the same is showing that either Sertoli cells are unable to produce AMH by a mutation in AMH gene or there is a resistance in the target structures due to a deficit of type II receptor of this hormone. Another logical consequence is the ipsilateral persistence of the uterine tube and in some cases of the uterus (male with uterus). The presence of bilateral cryptorchidism associated on one side with a uterine horn is characteristic of persistent Müllerian duct syndrome. The second and not least important fact of interest is that the testicle shows a gonadoblastoma. A rare finding in the testis of these patients, gonadoblastoma is much more frequent in the DSD with streak gonads. Also about a characteristic of its rarity is the fact that when these patients develop an infiltrative germ cell tumor (the risk is 18%) most of them do it to form a GCNIS.