Containing Both Germ Cell and Sex Cord-Stromal Elements

and Pilar González-Peramato2



(1)
Department of Anatomy, Histology and Neuroscience, Universidad Autónoma de Madrid, Madrid, Spain

(2)
Department of Pathology, University Hospital La Paz, Universidad Autónoma de Madrid, Madrid, Spain

 




Keywords

Testicular neoplasmsGonadoblastoma


Most tumors containing both germ cell and sex cord-stromal elements are characterized by combining in a harmonic way, in nests or cords, two cell types, germ cells (some similar to gonocytes) and cells of the sexual cords (similar to immature granulosa cells). This is the case of gonadoblastomas. The three cases of gonadoblastomas chosen are representative of the different gonads in which it can develop, one on a streak gonad of a patient with Frasier syndrome (gonadal dysgenesis 46, XY and nephropathy), another on a dysgenetic testis with AMH (dysgenetic male pseudohermaphroditism) deficit, and the third one in a gonad associated with seminoma of a patient with 46,XY gonadal dysgenesis. Throughout the three cases we expose: (a) the different patterns that may be present in the gonadoblastomas (nodular, dissecting) and the relationship with the undifferentiated gonadal tissue (UGT); (b) the evolution of this neoplasia either towards regression by calcification, or progression to a germ cell tumor; and (c) the differential diagnosis with other entities with which the gonadoblastoma has certain morphological similarity. This is the case of Sertoli cell nodules with infiltration by GCNIS or gonadoblastoid testicular dysplasia.


4.1 Gonadoblastoma



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.

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Fig. 1

Longitudinal section of the testicle. Loss of tubular architecture at the level of the upper pole. The gonadoblastoma is located at this level


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Fig. 2

Poorly collagenized albuginea with seminiferous tubules in its thickness and poor delimitation with testicular parenchyma are the typical lesions of a dysgenetic testicle


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Fig. 3

The gonadoblastoma is located at the periphery of the parenchyma. It consists of tubes and nodules of different sizes


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Fig. 4

Tumor nodules are well-defined spherical formations, surrounded by a dense stroma


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Fig. 5

Part of a tumor nodule. It shows two types of cells, most of them with small and pyknotic nuclei, and others of larger size, with clear cytoplasm, vesicular nucleus, and prominent nucleolus. Among them several eosinophilic bodies


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Fig. 6

Overview of the two components of gonadoblastoma in nests and tubules. A strong immunoexpression for inhibin is observed in both of them


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Fig. 7

The smaller cells (Sertoli/granulosa cells) show strong immunostaining for inhibin. Germ cells are negative


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Fig. 8

Nodular formation of gonadoblastoma. Germ cells have an intense positivity for PLAP


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.

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Oct 1, 2020 | Posted by in UROLOGY | Comments Off on Containing Both Germ Cell and Sex Cord-Stromal Elements
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