RESUMO
Hypogonadotrophic hypogonadism can result from different abnormalities in the central nervous system. The clinical picture depends upon the time of onset the deficiency, the magnitude of the gonadotropins deficiency and whether there are other pituitary hormone deficiencies as well. We report on a 18-year-old boy, who was investigated because of pubertal and growth delay. He also had learning disabilities. On physical examination he exhibited mild eunuchoid aspect, 162 cm height (z score = 2.17), pubertal development on stage G II, P II, and 4 cm3 testis. Laboratory investigation revealed pre-pubertal levels of testosterone and normal results of the combined test of anterior pituitary function, except for in GnRH acute and prolonged test. Brain CT showed an arachnoid cyst on left middle fossa with expansion to suprasellar cisterna. He was diagnosed as having hypogonadotrophic hypogonadism secondary to compression by the cyst, and a cyst-peritoneal derivation was performed. After surgery there was no improvement of the pubertal state and bilateral anosmia was discovered, so Kallmann's syndrome was then diagnosed and was confirmed by MRI, even though the hormonal results are not totally matched with the referred syndrome. We did not find in the literature any description of the association between Kallmann's syndrome and arachnoid cyst and we believe that in this case the results of the hormonal measurement may be due to such association that provoked an additional hypophysis dysfunction.