title: Thickened pituitary stalk on magnetic resonance imaging in children with central diabetes insipidus.
abstract: Magnetic resonance imaging (MRI) has revealed isolated pituitary stalk thickening (PST) in certain cases of idiopathic or secondary central diabetes insipidus (DI) due to infiltrative processes. Twenty-six children with DI and PST underwent cerebral MRI at the age of 8 +/- 4 years and were followed (n = 25) by clinical and MRI evaluation for 5.5 +/- 3.6 and 3.0 +/- 2 years, respectively, but given no treatment other than hormonal substitutive therapy. Patients were subdivided into groups according to the etiology of the DI: germinoma (n = 4), Langerhans' histiocytosis (n = 5) or 'idiopathic' DI with PST (n = 17). Complete anterior pituitary evaluation in 24 of the 26 patients revealed that 14 children were suffering from associated growth hormone deficiency and 7 had multiple hormone deficiencies. At the first MRI evaluation, pituitary stalk enlargement varied from 2.2 to 9.0 mm. The anterior pituitary gland was found to be normal (n = 12), small (n = 8) or enlarged (n = 6). At the final evaluation, a change in MRI features had occurred in 16 patients: morphological and/or signal changes in the PST (n = 16; 6 of whom showed an increase in PST) and changes in anterior pituitary gland size (n = 8; 3 of whom had increased and 5 had decreased). The presence of a growing suprasellar mass with a progressively enlarging pituitary stalk was demonstrated in the 6 patients who had shown increased pituitary stalk enlargement 1.8 +/- 1.6 years after the first MRI. In 4 of these patients, a diagnosis of germinoma was made 1.3 +/- 0.6 years after PST identification by MRI at the onset of DI, but the other 2 patients showing a suprasellar mass were still categorized as 'idiopathic' at the final clinical evaluation performed 7.8 and 12.3 years after DI onset. In 10 patients (all but 1 with Langerhans' histiocytosis, showing 'idiopathic' DI) the pituitary stalk enlargement was diminished after 2.0 +/- 1.9 years of MRI follow-up, and there was a complete reversal of pituitary stalk enlargement in 5 patients. We conclude that the natural history of 'idiopathic' isolated central DI with PST is unpredictable. Although germinoma should always be considered during the first 3 years of follow-up in patients presenting isolated DI with PST by repeated investigations every 3-6 months, it remains an infrequent etiology, affecting only 15% of cases in our study.
authors.affiliation: Pediatric Endocrinology and Diabetes Unit, Hôpital Robert-Debré, Paris, France.
authors.forename: P
authors.initials: P
authors.lastname: Czernichow
authors.forename: C
authors.initials: C
authors.lastname: Garel
authors.forename: J
authors.initials: J
authors.lastname: Léger
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003919:Diabetes Insipidus / Q000209:etiology / Q000473:pathology*; D005260:Female; D018237:Germinoma / Q000150:complications / Q000473:pathology; D006646:Histiocytosis, Langerhans-Cell / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010190:Pancreatic Neoplasms / Q000150:complications / Q000473:pathology; D010901:Pituitary Function Tests; D010902:Pituitary Gland / Q000473:pathology*