Ectopic Leydig cells in a seminiferous tubules of an infertile human male with a chromosomal aberration.

A case of a human male infertility with chromosomal aberration is reported. The patient showed neither mental retardation nor physical abnormalities except that the testes were somewhat small and soft. Plasma follicle stimulating hormone and luteinizing hormone were 49.0 and 19.0 mIU/ml. Plasma testosterone was 2.6 ng/ml. Karyotype was considered to be 46 XY q-, long arms of the Y chromosome being deleted. Histological features of the testis were peculiar. Seminiferous tubules were small and devoid of spermatogenic cells, consisting only of Sertoli cells. Peritubular boundary layer of the tubules showed a marked increase in width due to the increase of collagen fibers. The base of some Sertoli cells was seen to protrude into the thickened peritubular boundary layer or, though rare, into the interstitial space. Unusual cells which had a round vesicular nucleus and abundant, dense cytoplasms also occurred in the boundary layer of most tubules. These cells were identified as Leydig cells because of an extensively developed smooth endoplasmic reticulum in their cytoplasm, although they lacked Reinke's crystals. These ectopic Leydig cells sometimes lay in direct contact with Sertoli cells in the seminiferous tubule.