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.