[A study of cryptorchidism. I. Light and electron microscopic study of Leydig's cells in the testes of cryptorchid patients].

A morphological study of the Leydig's cells in the testes of cryptorchid patients was made by light and electron microscopy. Seventy four unilateral and bilateral cryptorchids (aged 2 to 37 years) were selected for light microscopic observation, and 28 of these specimens were also examined by electron microscopy. In 5 cases of pre-pubertal and pubertal cryptorchids, tissue specimens were biopsied after 20,000 units of HCG had been given and examined similarly. In addition, Leydig's cell density was evaluated quantitatively in the undescended and contralateral scrotal testes of 12 post-pubertal patients. This was based on the determination of the total number of Leydig's cells, Leydig's cell clusters and seminiferous tubules in the entire histologic section of each biopsy and the calculation of the following indices; mean number of Leydig's cells per tubule, mean number of Leydig's cell clusters per tubule and mean number of Leydig's cells per cluster. In addition, the number of Sertoli's cells was counted, and the ratio of Leydig's cells to Sertoli's cells was also calculated. In the undescended testes, almost no mature Leydig's cells were found by light or electron microscopy during pre-pubertal periods; and, even in puberty they were few, while immature precursor Leydig's cells were abundant. In the 5 cases treated preoperatively with HCG, even at 5 years, mature Leydig's cells were observed by light and electron microscopy. On the contrary, after puberty, not only the undescended but also the contralateral scrotal testes of the cryptorchids had more mature Leydig's cells than the normal controls. This Leydig's cell hyperplasia was also confirmed by the quantitative analysis of Leydig's cell density. In the mature Leydig's cells of the undescended testes, however, the electron microscopic observation showed marked regressive changes, in cytology especially prominent depletion of the smooth endoplasmic reticulum and frequent occurrence of specific cytoplasmic inclusion bodies. Such regressive changes as found in the cells of the undescended testes were not observed in the cells of the contralateral scrotal testes. Thus, the morphological alteration of Leydig's cells observed here suggest that the cells are in a dysfunctional condition and that the androgen production is consequently decreased in the undescended testes of cryptorchid patients.