The case of a 15-yr-old boy with C11 hydroxylase deficiency congenital adrenal hyperplasia is reported who was diagnosed and treated as true precocious puberty at the age of 2 yr because of virilization and bilateral testicular enlargement. He later developed hyperpigmentation, hypertension and short stature and because of an increase in testes size he underwent testicular biopsy with the assumption of Leydig cell tumor. With the intake of glucocorticoids his testes size, hypertension and hyperpigmentation improved markedly. We could find only 6 such cases in the literature and have reviewed their clinical and laboratory data. All patients showed the picture of virilization with hypertension. Leydig cell tumor was proposed as the differential diagnosis in all cases except ours. Ultrasonography was able to show testicular adrenal-like tissue in all those in whom the procedure was undertaken. In the 5 patients of whom we could find enough data, 1 responded partially and 4 responded markedly to corticosteroid therapy with shrinkage of testicular tumors. We conclude that clinical findings and US are very important in the early diagnosis of these patients and with adequate treatment most cases show shrinkage in testicular tumors.