Congenital Leydig cell hyperplasia.

The testes and epididymes collected at autopsy from 21 newborns showed apparent Leydig cell hyperplasia which was studied by light and electron microscopy. Twelve newborns were the sons of diabetic mothers, two had undergone rhesus isoimmunization, two were twins of a non-diabetic mother, three had Beckwitz-Widemann's syndrome, and two had leprechaunism. In the first two groups the placentas were also collected and studied. All the testes showed normal seminiferous tubules and diffuse Leydig cell hyperplasia in the testicular interstitium. In addition one son of a diabetic mother and another with Beckwitz-Widemann's syndrome presented multiple Leydig cell nodules in the mediastinum testis and epididymis. The number of Leydig cells per unit area of the testis was calculated on histological sections stained with the peroxidase-anti-peroxidase method for the detection of testosterone. These numbers varied from 1.4 to 3.2 times those found in age-matched controls, except for the two testes with nodular hyperplasia in which the increase in Leydig cells was even greater. The differential diagnosis between Leydig cell hyperplasia, ectopic adrenal cells and leydig cell tumour is discussed. It is proposed that the cause of congenital Leydig cell hyperplasia might be related to placental secretion of human chorionic gonadotrophin.