[Findings: small testicles]

Small testicles are normal in prepubertal boys, irrespective of their height and weight. Small testicles associated with premature sexual development (pseudopuberty) usually reflect an alternate source of androgens, most frequently adrenal (e.g. in congenital adrenogenital syndrome). Small testicles as a result of testicular atrophy are either the consequence of a painful event such as mumps-orchitis or trauma (such as torsion), or a side effect of extratesticular disease (such as liver cirrhoses, chronic alcoholism, haemochromatosis, Curschmann-Steinert dystrophic myotonia etc.). Certain drugs (e.g. immunosuppressive and chemotherapy) and irradiation may also lead to testicular atrophy. Cryptorchidism as the expression of prenatal testicular damage may lead to an "incompetent", i.e. small, testis even if properly descended by surgery. However, a small testis after orchidopexy may also be the consequence of injury to blood vessels during surgery. The cryptorchid testis has an increased though still low incidence of malignancy, but a markedly elevated rate of sterility. Probably the most frequent cause of small testicles is Klinefelter syndrome (XXY/47), involving a wide spectrum from eunuchoid hypogonadism to a normally virilized albeit sterile male, in whom gynecomastia is not much more frequent than in the average male population but in whom the mammary cancer risk is definitely elevated almost to female rates.