[A case of hypogonadotrophic hypogonadism causing lumbar stress fracture].

A 57-year-old man was referred to our hospital for further evaluation on hypogonadotrophic hypogonadism causing a stress fracture of the 4th lumbar vertebrae. Azoospermia had been pointed out at the age 30, but hormonal evaluation had not been performed. Physical examination revealed an eunuchoidal body proportion, a stretched phallus length of 4 cm and bilateral scrotal testes of 6 ml. Hormonal evaluation demonstrated a testosterone level of 13 ng/dl (normal, 320 to 1,030 ng/dl), a luteinizing hormone of 0.2 mU/ml (normal, 1.8 to 9.2 mU/ml) and a follicular stimulating hormone of 1.0 mU/ml (normal, 1.6 to 10.7 mU/ml). Results of a stress test of gonadotrophin-releasing hormone was a low delay type. Computerized tomography showed no abnormality in the hypothalamic-pituitary region. The patient was treated with the substitution therapy of androgen. The therapy was discontinued 6 months later because of severe nipple pain. We should perform hormonal evaluation and other examinations for male infertility.