ABSTRACT
Gonadal dysgenesis is characterized by failure of anatomical and functional development of gonads or regression of primary germ cells, transformed to a connective tissue similar to ovarian cortex. According to chromosomal constitution their varieties of clinical manifestations, including Turner syndrome, pure female gonadal dysgenesis consist of 46,XX biletaral streak gonads without Turner stigmas, male XY pure gonadal dysgenesis [Swyer syndrome] with 46,XY bilateral streak gonads and mixed gonadal dysgenesis with streak gonad in one side and dysgenetic testes in epilateral side, usually with 45,X/46,XY mosaicism. Among 1207 cases with primary amenorrhea as main complaint, there are 109 cases with total or mosaic chromosome Y. There are 10 cases of malignant transformation; seven among 35 cases of Swyer syndrome and three cases among 25 cases of mixed gonadal dysgenesis. These findings confirm the risk of Y chromosome to enhance the malignant transformation in dysgenic gonads and express on prophylactic bilateral gonadectomy before the age of adolescence in these cases