[MRI pituitary stalk abnormalities: etiology aspects in 11 patients]

Newer techniques of magnetic resonance imaging (MRI) describe more accurately pituitary stalk abnormalities such as infections, infiltrative lesions and tumors. In absence of all the above mentioned etiological factors, genetics defects are suspected, mainly when other malformations are equally present. We attempt to show through 11 observations the variability of pathologies involving the pituitary stalk with their respective clinical and radiological features and associated endocrine abnormalities. This is a retrospective study of 7 men (67%) and 4 women (33%), mean age of 28 year (range: 15 to 53) in whom pituitary MRI was performed for hypopituitarism, diabetes insipidus or hyperprolactinemia. Three patients had brain MRI for an extra-pituitary condition. The pituitary MRI showed a stalk section in 3 cases (27%), atrophy in 1 case and thickening in 7 cases (67%). The pituitary stalk anomaly was associated with hyperprolactinemia in 3 cases (27%), central diabetes insipidus in 4 cases (36%), growth hormone deficiency in 4 cases (36%), adrenal insufficiency in 5 cases (45%), hypogonadism in 5 cases (45%) and hypothyroidism in one case (9%). Established diagnoses were: sellar metastasis in 2 cases (18%), Langerhans' histocytosis, tuberculosis and autoimmune hypophysitis respectively in 3 cases (9%). In 6 cases (54%), no clear etiology was found. Given the multitude of pituitary stalk pathologies, a detailed etiologic inquiry must be performed in order to detect elements able to reclassify an initially idiopathic disorder.