Endocrine Abstracts

Only small advances were made in the field of pituitary imaging until the advent of magnetic resonance imaging (MRI), which led to an enormous increase in our detailed knowledge of pituitary morphology, thus improving the differential diagnosis of hypopituitarism. Indeed, MRI represents the examination method of choice for evaluating hypothalamic–pituitary-related endocrine diseases thanks to its ability to provide strongly-contrasted high-resolution multi-planar and spatial images. Specifically, MRI allow a detailed and precise anatomical study of the pituitary gland by differentiating between the anterior and posterior pituitary lobes. The MRI identification of pituitary hyperintensity in the posterior part of the sella, now considered a marker of neurohypophyseal functional integrity, has been the most striking finding contributing to the diagnosis and understanding of some forms of ‘idiopathic’ and permanent GH deficiency (GHD).

Published data show a varying correlation between pituitary abnormalities as observed on the MRI scan and a patient’s endocrine profile. Indeed several trends have emerged and have been confirmed: i) normal MRI scan or anterior pituitary hypoplasia mainly indicates isolated GHD that is generally transient and not confirmed after adult height achievement; ii) patients with MPHD seldom have a normal pituitary gland and iii) the classic triad of ectopic posterior pituitary gland, pituitary stalk hypoplasia/agenesis and anterior pituitary gland hypoplasia is more frequently reported in MPHD patients and its generally associated with permanent GHD. Pituitary abnormalities have been reported in patients with GHD carrying mutations in several genes encoding transcription factors such as POU1F1, PROP1, HESX1, LHX3, LHX4, GLI2, PITX1, PITX2, SOX3, SOX2 and OTX2. Establishing endocrine and MRI phenotypes is extremely helpful in the selection and management of patients with hypopituitarism, both in terms of possible genetic counseling and of early diagnosis of evolving anterior pituitary hormone deficiencies.