A Case of Ectopic Neurohypophysis Presenting with Hypogonadism

Pituitary stalk interruption and ectopic neurohypophysis seen on magnetic resonance Imaging (MRI) are often associated with either isolated growth hormone (GH) deficiency or combined anterior pituitary hormone deficiency, but their pathogenesis is not clear and the clinical data regarding these anatomical defect is limited. We experienced a 23-year-old male with the absence of secondary sexual characteristics and this was accompanied with pituitary stalk dysgenesis and ectopic neurohypophysis. He received growth hormone for a year when he was 12 years old due to his short stature. Sella MRI showed no visible pituitary stalk with minimal high signal change, suggesting ectopic neurohypophysis. The combined pituitary stimulation test revealed blunted responses of growth hormone, follicle stimulating hormone and luteinizing hormone. For the hypogonadotropic hypogonadism, the patient was given testosterone intramuscularly and he gradually developed secondary sexual characteristics. We concluded that the hypogonadism and growth hormone deficiency in this patient was caused by hypopituitarism due to pituitary stalk dysgenesis and ecopic nuerohypophysis.

A Case of Delayed Puberty due to Hypoplasia of Anterior Pituitary Gland with Pituitary Stalk Agenesis and Ectopic Neurohypophysis / 대한내분비학회지

Hypopituitarism is not a common cause of delayed puberty, however it should always be considered, especially if there are such signs as severe dwarfism, dollish face, truncal obesity, small hands and feet, and microgenitalia. Either congenital or acquired, hypopituitarism can be resulted from hypothalamic and hypophyseal lesions. The clinical feature can be diverse depending on age of the patients, rate of progression, degree of hormone deficiency and characteristics of the lesion. The recent high interest in delayed puberty and the improved detection of hypothalamic hypophyseal lesions using combined pituitary fuction stimulation test, brain CT and MRJ, has made the differential diagnosis of hypopituitarism possible as the cause of delayed puberty. MRI has shown hypophyeal hypoplasia accompanied by anterior pituitary hypoplasia and ectopic neurohypophysis in some of the patients with hypopituitasm, and although the anatomical abnormality around the hypophysis in these patients is considered the reason for hypopituitarism, the pathogensis of which has not yet to be known. We, here, report a case of delayed puberty by hypopituitarism due to hypoplasia of anterior pituitary gland, pituitary stalk agenesis and ectopic neurohypophysis with brief review of the litereature.