DYSGERMINOMA WITH SYNCYTIOTROPHOBLASTIC GIANT-CELLS ARISING FROM 46,XX PURE GONADAL-DYSGENESIS

Background: Dysgerminoma with syncytiotrophblastic giant cells is a ra re ovarian tumor. Only ten cases of this tumor have been reported, and all tumors developed in normal ovaries. This report presents a case o f dysgerminoma with syncytiotrophoblastic giant cells arising in a pat ient with 46,XX pure gonadal dysgenesis. Case: An 18-year-old phenotyp ic female of normal height without somatic anomalies with nonfunctiona l ovaries underwent a bilateral gonadectomy for a right ovarian tumor and left streak gonad. The tumor revealed a dysgerminoma containing sc attered syncytiotrophoblastic giant cells. Her serum hCG was elevated, and hCG was demonstrated within syncytiotrophoblastic giant cells imm unohistochemically. The clinical diagnosis was stage Ia dysgerminoma w ith syncytiotrophoblastic giant cells. Her karyotype was 46,XX and the sex-determining region Y gene was not detected in tumor DNA by polyme rase chain reaction analysis. Conclusion: This rare gonadal tumor may arise from dysgenetic gonads in addition to gonadoblastoma and pure dy sgerminoma. It is an example of tumorgenesis in pure gonadal dysgenesi s with no identifiable Y chromosome component. (Obstet Gynecol 1998;92 :654-6. (C) 1998 by The American College of Obstetricians and Gynecolo gists.)