Disorders involving androgen excess due to congenital adrenal hyperplasia, virilising adrenal tumours or Leydig cell tumours, share the feature of incomplete sexual precocity. In congenital adrenal hyperplasia there will be no enlargement of the testes, since circulating androgens suppress endogenous gonadotrophin secretion. Adrenal rests in the testes, or Leydig cell tumours of the testes, will lead to irregular enlargement of the testes: the former are due to ACTH stimulation, and the latter to tumour formation.
