Gonadoblastoma: clinicopathologic correlation in six patients

In situ hybridization analysis of the Y chromosome in gonadoblastoma

Gonadoblastoma is a rare tumor arising in the streak gonads of about 30% of 46,XY sex-reversed females. Because gonadoblastoma develops only in patients who have Y-chromosome material and dysgenetic gonads, it has been hypothesized that positive expression of a gene (or genes) on the Y chromosome (GBY) is involved in the etiology of the tumor. To examine the Y chromosome directly in tumors, we performed nonisotopic in situ hybridization of a biotin-labeled Y-specific probe for the DYZI locus on formalin-fixed, paraffin-embedded sections of tumor samples from four different patients. After hybridization to DYZI, the Y chromosome was found to be present in all gonadoblastoma foci in the four patients studied, and the gonadoblastoma foci showed an average of 85% cell nuclei positive for the Y chromosome on tissue sections. Normal male and female control tissues showed an average of 78% and 0% positive nuclei, respectively. One patient with bilateral gonadoblastoma had previously been shown to be mosaic, with a 45,X/46,XY karyotype in lymphocytes, skin fibroblasts, and cultures from both gonads. Examination of sections of this patient's gonads showed 79% positive nuclei within the gonadoblastoma foci, whereas the nontumor stromal tissue had 19% positive nuclei. These results indicate that, in this mosaic gonad, tumor foci developed only from cells that had a Y chromosome. Our results support the hypothesis that there is a GBY locus on the Y chromosome and that the Y chromosome is retained in the gonadoblastoma foci during the development of the tumor.

Gonadal tumors in disorders of sexual differentiation

OBJECTIVE

To study the prevalence and distribution of gonadal tumors in patients with disorders of sexual differentiation.

METHODS

Retrospective review of pathologic materials and clinical data on all patients diagnosed with mixed gonadal dysgenesis, pure gonadal dysgenesis, androgen insensitivity, and true hermaphroditism between 1982 and 1990.

RESULTS

Twenty-one patients were identified and all underwent bilateral gonadectomy at the time of diagnosis. Nine of 21 patients had a gonadal tumor for a prevalence of 44 percent. Those at greatest risk for tumor were patients with mixed gonadal dysgenesis (6 of 11 patients) and pure gonadal dysgenesis (2 of 3 patients). There were four gonadoblastomas, two dysgerminomas, and one each of teratocarcinoma, seminoma, cystadenofibroma, and juvenile granulosa cell tumor.

CONCLUSIONS

The high prevalence of gonadal tumors in children with mixed and pure gonadal dysgenesis warrants consideration of early, bilateral, prophylactic gonadectomy once the diagnosis is established with certainty.

Dysgerminoma in 45,X Turner syndrome: report of a case

Here we report the fourth case of dysgerminoma in a patient with the syndrome of gonadal dysgenesis and 45,X karyotype. Typical Turner's syndrome features were unusually associated with breast development, menarche and secondary amenorrhoea. Exaggerated basal and GnRH stimulated gonadotrophin and low oestradiol levels were typical of post-pubertal Turner's syndrome. Detailed (standard) chromosome and banding analysis excluded the presence of Y chromosome material. This case suggests that the presence of a Y chromosome is not necessary for abnormal differentiation of germ cells and the occurrence of a gonadoblastoma.

Gonadoblastoma and Y-chromosome fluorescence

In this report we summarize our experience in 4 patients with 45,X/46,XY, one patient with 45,X/47,XYY mosaicism, and one patient with 46,XY karyotype and ambiguous external genitalia. In the 3 patients with a fluorescent Y-chromosome, the development of one or two gonadoblastomas was found, independent of the age of the patients at the time of examination. In the 3 patients with 45,X/46,XYnf mosaicism no gonadoblastoma was detected. This finding prompted us to review the data on patients reported with 45,X/46,XYnf mosaicism. Up to now, no patient with well documented 45,X/46,XYnf mosaicism and convincing evidence of development of gonadoblastoma has been reported. These data seem to confirm that alterations of the characteristic distal fluorescence of Yq may protect the dysgenetic gonad against tumoral degeneration in patients with 45,X/46,XY mosaicism. Possible mechanisms responsible for these changes in the oncogenic potential of Yq in relation with the Y chromosome fluorescence are discussed.

Invasive dysgerminoma in a girl with 45,X/46,X; mar mosaicism

We report a 16-year-old girl with features of Turner's syndrome from whom an invasive dysgerminoma was removed. Cytotoxic drugs were given for the next 12 months. Mosaicism of two karyotypes (45,X/46,X; mar) was found in various tissues. The literature is reviewed with special regard to cytogenetic findings and prognosis of malignant growth and differentiation of dysgenetic gonads.

Dysgenesis of testicular and streak gonads in the syndrome of mixed gonadal dysgenesis: perspective derived from a clinicopathologic analysis of twenty-one cases

The clinical and pathologic aspects of 21 cases of mixed gonadal dysgenesis (MGD) were studied. The gonads in 15 patients consisted of a macroscopic testis and a streak gonad; six patients had variants, including two with bilateral testes and four with bilateral streak gonads or tumors. Functionally, the gonads were incompetent. Testes 1) failed to completely inhibit müllerian development, 2) failed to support full differentiation of mesonephric duct structures, 3) failed to adequately masculinize development of the external genitalia, or 4) often failed to mediate their own descent, resulting in asymmetry of the internal and external genitalia. None of the streak gonads mediated normal female adolescent development or fertility. Microscopic examination revealed that every gonad, regardless of its gross appearance, was morphologically abnormal. Although gonads with seminiferous tubules usually developed to a moderately advanced state, macroscopically resembling testes, the hilar zone remained architecturally disorganized; the cortex invariably lacked more than a rudimentary tunica albuginea or exhibited partial ovarian differentiation, sometimes even with a rare primordial follicle. Over time, the seminiferous tubules atrophied and hyalinized. Gonads that grossly resembled streak gonads were observed microscopically to be composed of a stroma resembling that of normal ovarian cortex. In patients more than several years of age, the entire complement of germ cells in streak gonads disappeared. It is suggested that patients with MGD be raised as females. Early removal of gonads will prevent the development of gonadoblastoma and dysgerminoma. If the uterus is retained and the patient is subsequently given exogenous estrogen, care should be taken to detect early any signs of the development of endometrial carcinoma or its precursor, to which these patients may be prone.

Hormonal and cytogenetic studies in phenotypically female patients with gonadal dysgenesis

In 4 cases of gonadal dysgenesis the clinical, hormonal, cytogenetic, and histological findings were correlated. There were 2 patients with 46,XY karyotype, one patient with 45,X Turner's syndrome and one patient with a 46,XX chromosome complement. All patients had streak gonads with ovarian stroma. In one phenotypically female 46,XY individual an involuted gonadoblastoma was found. Her testosterone was four-fold higher in gonadal vein blood compared to peripheral blood. Cytogenetic analysis of multiple tissues in both cases with the 46,XY karyotype greatly reduced the probability of mosaicism. In the patient with 45,X Turner's syndrome and in the one with 46,XX gonadal dysgenesis only peripheral blood cells were karyotyped and mosaicism was not further excluded by analysis of other tissues. The concentrations of steroid hormones in gonadal vein blood were low. The levels ranged as follows: estrone 41-98 pg/ml, estradiol 18-90 pg/ml, testosterone 37-294 ng/100 ml, dihydrotestosterone 13-22 ng/100 ml, and progesterone 0.3-1.5 ng/ml. It was concluded that gonadal streaks were similarly deficient in biosynthesis of steroid hormones despite different chromosomal complements.

Germ cell neoplasms arising in gonadoblastomas

Gonadoblastomas have a propensity to give rise to germ cell neoplasms. This study analyzes the clinicopathologic findings in six phenotypic females with features of 46,XY pure gonadal dysgenesis who developed germinomas and other germ cell tumors in gonadoblastomas. All stages in the evolution of germinoma from the germ cells of gonadoblastoma were observed, including in situ, incipient, microinvasive, and metastatic varieties. Admixtures with teratoma and endodermal sinus tumor occurred in two patients. Germ cell tumors which originate in gonadoblastomas appear to have the same clinical behavior and response to therapy as those that arise de novo in the ovary, testis or extragonadal sites. Although it is debatable whether gonadoblastomas are true neoplasms or blastomatoid dysgenetic malformations, their potential for giving rise to fully malignant germ cell neoplasms must be recognized.