Mixed gonadal dysgenesis, pathogensis, and management.

Fourteen patients with Mixed Gonadal Dysgenesis who presented as infants or children are discussed. Gonadal asymmetry, and/or sex chromosomal mosaicism, as well as retained Mullerian Ducts characterize the anomaly. The dysgenetic testis may occur as the result of a cascade of development mishaps stemming from abnormalities of H-Y antigen expression or function that lead to abnormal differentiation of the indifferent urogenital ridge and, in turn, to aberrant production of Mullerian inhibiting Substance and testosterone. The latter two cause retention of Mullerian ducts and incomplete masculinization of the external genitalia. Absence of a second X chromosome may lead to the formation of a streak ovary, in which the dysgenetic testis may invoke formation of hilar and medullary cords. Neoplastic transformation, so characteristic of this group of patients, may result from unprotected germ cells and abnormally high and prolonged gonadotropin stimulation. Gonadoblastoma and seminoma-dysgerminomas are the tumors found in the gonads with the risk exceeding 50% as the third decade is approached. Laterality of the gonads in this anomaly remains an enigma. The gonads should be removed at birth if possible and the external genitalia repaired soon thereafter. These patients should be raised as females. The risk of neoplastic transformations must be considered at all stages of management.