Gonadoblastoma in a patient with an isodicentric X chromosome

Clinical pathologic correlation: primary amenorrhoea and bilateral adnexal tumors

A case of bilateral gonadoblastoma in 46,XY gonadal dysgenesis is presented and discussed by both clinician and pathologist, in this traditional clinico-pathologic conference. The discussion includes the differential diagnoses of primary amenorrhoea.

Neuropsychiatric disturbances in a patient with a nonmosaic isodicentric (X) (q21.32) chromosome

A 41-year-old female patient with mental retardation and generalized epileptic seizure had a nonmosaic idic (X) (pter-q21.32::q21.32-pter) chromosome in peripheral lymphocytes and bone marrow cells. Primary amenorrhea, myelodysplastic syndrome, pigmented nevi and characteristic facial appearance were also observed. A few cases with the nonmosaic idic (X) (q::q) with various breakpoints reported previously commonly showed ovarian failure with dysfunction of relevant hormone. CNS abnormalities of the present case were demonstrated by CT, MRI and SPECT using 123I-IMP. CNS abnormalities were considered to be possibly due to karyotype with a nonmosaic idic (X) (q21.32).

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.

Abnormal sexual differentiation and neoplasia

The prevalence of neoplasia is increased in individuals with certain disorders of sexual differentiation. Etiology and frequency of neoplasia vary with the particular disorder. In uncomplicated cryptorchidism, the testis is at least 10 times more likely to undergo neoplastic transformation than a normal scrotal testis. Neoplasia probably is a function of both testicular location (intraabdominal) and underlying dysgenetic structure. If cryptorchidism is unilateral, and if orchiopexy has not been performed prior to age 6-10 years, orchiectomy should be encouraged. In those forms of gonadal dysgenesis not associated with a Y chromosome (e.g., 45,X; 45,X/46,XX; 46,XX) there is no definite increase in neoplasia, suggesting that elevated gonadotropin levels per se are not carcinogenic. Gonadal tumors are found in at least 30% of individuals with XY gonadal dysgenesis and are particularly frequent (55%) in H-Y antigen-positive patients. These tumors are almost always gonadoblastomas or dysgerminomas. Similar tumors are found in 15%-20% of 45,X/46,XY individuals. In either situation the neoplastic transformation could be a) secondary to the existence of XY gonadal tissue in an inhospitable environment, or b) integrally related to that process--genetic or cytogenetic--producing the dysgenetic gonads. The risk of neoplasia is sufficiently high that most of these patients should be offered early gonadal extirpation. The prevalence of gonadal tumors is not increased in Klinefelter's syndrome, further indicating that gonadotropins are not carcinogenic per se. However, Klinefelter patients are 20 times more likely to develop a carcinoma of the breast than are 46,XY males. Extragonadal germ cell tumors also are more common. In female pseudohermaphrodites there is probably no increased risk of neoplasia, whereas, in true hermaphrodites neoplasia is unusual but does occur. Neoplasia occurs in patients with complete testicular feminization (complete androgen insensitivity) but rarely in those with incomplete testicular feminization/Reifenstein's syndrome, 5 alpha-reductase deficiency, anorchia, agonadia, or testosterone biosynthetic defects. In complete testicular feminization the risk of malignant tumors is small prior to age 25. After age 25, it is about 2%-5%. Orchiectomy is recommended after pubertal feminization.

Three related centromere proteins are absent from the inactive centromere of a stable isodicentric chromosome

We developed an aqueous spreading procedure that permits simultaneous analysis of human chromosomes by Q-banding and indirect immunofluorescence. Using this methodology and anticentromere antibodies from an autoimmune patient we compared the active and inactive centromeres of an isodicentric X chromosome. We show that a family of structurally related human centromere proteins (CENP-A, CENP-B, and CENP-C) is detectable only at the active centromere. These antigens therefore may be regarded both as morphological and functional markers for active centromeres.