[Morphological studies of the Leydig cells in impaired fertility]

The histological results of 242 testicular biopsies in the period from 1974 to 1983 were evaluated with special consideration of the Leydig cells. Normal spermatogenesis was found in 9.5% of cases, hypospermatogenesis with and without maturation arrest in 76.4%, also Sertoli-cell-only and Klinefelter's syndrome in 11.6% and 2.5% respectively. Frequently an increase as well as a decrease of Leydig cells were observed in cases with pathological findings in these biopsies. In patients with Klinefelter's syndrome only an increase of Leydig cells could be seen. Ultrastructural investigations have shown that there were degenerative alterations of nucleus and cytoplasm in the Leydig cells of pathological biopsies, which could not be seen with light microscopy. In one patient with Klinefelter's syndrome needle-like crystalloid inclusions of unknown genesis were found in cytoplasm.