Risk of malignancy in bilateral streak gonads: the role of the Y chromosome.

Although girls with Turner's syndrome (45,X) are not at risk for malignancy, patients with feminizing testicular syndrome with XY chromosome composition and patients with "mixed gonadal dysgenesis" are at risk for malignancy, and bilateral gonadectomy is performed. We have treated seven girls with "Turner-like" syndrome, who we believe are also "at risk" for development of malignancy and in whom gonadectomy should be performed. We present seven cases of phenotypically typical females, without sexual ambiguity, who presented with primary amenorrhea and short stature (5) and/or minor dysmorphic features (2). Chromosome analysis showed 45,X karyotype plus a fragment that we could not rule out as being part of a Y chromosome (in one patient a complete Y chromosome). In two patients, the fragment was subsequently positively identified as a Y, using a DNA probe. In view of the known high incidence of development of gonadoblastoma in the dysgenetic gonads of phenotypic females with a Y chromosome, bilateral gonadectomy was performed in these girls. Bilateral genital streaks with normal uterus and Fallopian tubes were found in all patients. In two patients unsuspected gonadoblastoma, without metastases, was found. In five cases, Leydig cells and tubular structures resembling rete testes were found, cells that are associated with Y-chromosomal tissue. We stress the need for complete chromosomal evaluation of phenotypically female patients with primary amenorrhea or features of Turner's syndrome. If a Y chromosome or the possibility of a Y chromosome cannot be excluded, gonadectomy should be performed because of the risk of malignancy.