SEMINOMA IN A POSTMENOPAUSAL WOMAN WITH A Y-15 TRANSLOCATION IN PERIPHERAL-BLOOD LYMPHOCYTES AND A T(Y-15) 45,X TURNER MOSAIC PATTERN IN SKIN FIBROBLASTS/

We report an unusual case of a 55 year old Japanese woman with a semin oma but relatively normal menses. The patient was a phenotypic female with late onset menarche (18 years of age), who was amenorrhoeic for t he first year, followed by menses of one to three days' slight flow wi th dysmenorrhoea, but an otherwise normal menstrual history. A typical seminoma was removed from the left adnexal region and an immature tes tis was identified separately as an associated right adnexal mass. Rep eated karyotypic studies on peripheral blood lymphocyte cultures showe d only 46,X,-Y,t(Y;15) (q12;p13). Cytogenetic examination of the patie nt's younger brother, who had fathered three healthy children, showed an identical karyotype. Mosaicism of 46,X,-Y,t(Y;15)(q12;p13)/45,X cel l lines was found in skin samples from the patient's elbow and genital regions, although there were no clinical stigmata of Turner syndrome. An androgen receptor binding assay of cultured genital skin fibroblas ts was negative. Molecular analysis using Southern blot hybridisation, PCR, and direct DNA sequencing showed that neither the patient nor he r brother had a detectable deletion or other abnormalities of Y chromo some sequences, including the SRY (sex determining region of the Y chr omosome) gene sequence. These findings suggest that Turner mosaicism o f the 45,X cell line may have contributed to this atypical presentatio n in an XY female, although we cannot exclude abnormalities of other g enes related to sex differentiation.