Studies on gonadal dysgenesis: variable expressivity of the XY testicular dysgenesis syndrome; two case reports.

Two adult unrelated XY phenotypically female individuals with sexual infantilism and genital ambiguity were studied. Mosaicism was ruled out by the assessment of a normal 46,XY karyotype in four different cell lines. Persistently elevated LH and FSH serum levels with concomitant normal pituitary Gn-RH responsiveness were found. Baseline serum testosterone concentrations were low, but they exhibited a slight though significant rise following HCG stimulation. Surgical and histological findings included the presence of Mullerian and Wolffian derivatives and small bilateral dysgenetic testes with absence of germ cell epithelium, scarce Sertoli cells, and hyperplastic Leydig cells. The overall data indicated an anatomo-functional testicular impairment particularly confined to the tubular compartment. By comparing the clinical and endocrine features of this incomplete form of the XY testicular dysgenesis with the complete and other unusual forms, further evidence is provided of a wide heterogeneity of the syndrome, and a more detailed classification is proposed.