[A case of Kallmann syndrome with empty sella and arachnoid cyst].

We report a 28-year-old man of Kallmann syndrome with arachnoid cyst and empty sella. At age 22, he was admitted with acute slipped capital epiphysis and diagnosed as primary hypogonadotropinemia, because of no response to LH-RH before and after 7-day LH-RH injection. He was treated with androgen for only one year. On his second admission due to femoral head necrosis at age 28, the endocrinological evaluation suggested hypothalamic hypogonadotropinemia. Although he had mild hyposomia, we diagnosed him as Kallmann syndrome, because abnormalities of rhinencephalon was present on MRI. Arachnoid cyst in the middle cranial fossa and empty sella were also observed on MRI and the ballooning of the sella had been advanced on plain X-ray for these 6 years. As Kallmann syndrome is known to be accompanied with midline craniofacial anomalies, the dysplasia of sellar diaphragm might be originated by the same pathogenesis. In this case, empty sella might be caused by impaired CSF dynamics due to arachnoid cyst as well as possible constitutional anomaly of the diaphragm.