[A case of Kallmann syndrome: diagnostic usefulness of cranial magnetic resonance imaging].

We report a case of Kallmann syndrome in which the cranial magnetic resonance imaging (MRI) findings of the olfactory tract were useful in making the diagnosis. A 20-year-old male who complained of delayed puberty was referred to our hospital in November 1998. He presented with hypogonadism and anosmia. The plasma levels of testosterone, luteinizing hormone (LH) and follicle stimulating hormone (FSH) were low. Pituitary and Leydig cell functions were normal by the LH-releasing hormone test and human chorionic gonadotropin (hCG) loading test, respectively. The karyotype was normal (46, XY). The smell test showed anosmia. After administration of hCG, a good response of plasma testosterone level and masculinization were recognized. Cranial MRI findings revealed an absence of olfactory bulbs and hypoplastic olfactory sulci. These MRI findings are characteristic of Kallmann syndrome and allowed us to confirm our diagnosis, in addition to classically used endocrinological and olfactory examination.