Background: Magnetic resonance imaging (MRI) of the hypothalamic-pituitary area is extremely useful in the investigation of patients with central diabetes insipidus (CDI) due to infiltrative processes.
Objective: We aimed to associate pituitary stalk thickness with the etiology of CDI and hormone deficiencies.
Method: A retrospective single-center study of 15 patients (four boys and 11 girls) with CDI was performed and clinical-epidemiological data and MRI characteristics studied. Median age at diagnosis of CDI was 9.7 years (range 1.315.6). The pituitary stalk was measured at its transversal part. Thickened pituitary stalk (TPS) was considered as >3 mm, (mild 3.13.9 mm, moderate 46.5 mm and severe >6.5 mm).
Results: At the first MRI evaluation, pituitary stalk enlargement in seven patients varied from 4 to 30 mm (mild n=1, moderate n=1 and severe n=5). A diagnosis of germinoma was made in five of them (PST severe). Of the eight patients without TPS, two were diagnosed with Langerhans histiocytosis (LCH) and six of idiopathic CDI (ICDI). Follow-up MRI was performed in eight patients without etiological diagnosis. Stalk increase was demonstrated in four of them (moderate n=3, severe n=1) in median time interval of 2.98 years (range 2.0811.24). They were diagnosed with germinoma (n=3) and idiopathic (n=1) CDI. Stalk morphology was heterogeneous in patients with germinoma (normal=1, uniform=1, pyramid=2, V-shaped=2, round=2), uniform in LHC, and normal in half of the patients with ICDI. Two patients had GH deficiency and eight patients had combined hormone pituitary deficiency (germinoma=7). Etiology of CDI was germinoma (n=8), LCH (n=2) and idiopathic (n=5).
Conclusions: i) Germinoma is the most common cause of CDI in childhood and adolescence; ii) The greatest degree of pituitary stalk thickness is associated with combined hormone pituitary deficiency.
Funding: CIBEROBN. Instituto de Salud Carlos III and Fundación Endocrinología y Nutrición. Madrid, Spain.
01 Oct 2015 - 03 Oct 2015