Characteristic location and growth patterns of functioning pituitary adenomas: correlation with histological distribution of hormone-secreting cells in the pituitary gland

Imaging of Sella and Parasellar Region

The sellar and parasellar region is complex, with a unique meningeal, neural, vascular, and bony anatomy. Understanding the imaging anatomy is critical for accurate imaging interpretation. resonance (MR) imaging is the primary modality for pituitary imaging, whereas computed tomography may be used when MR imaging is contraindicated, and provides complementary bony anatomic information. This article reviews embryology and anatomy of the sellar and parasellar region. Imaging appearances of pituitary adenomas, Rathke cleft cysts, meningiomas, craniopharyngiomas, arachnoid cysts, vascular disorders, infectious abnormalities, and pituitary apoplexy are discussed and illustrated.

MRI criteria of subtypes of adenomas and epithelial cysts of the pituitary gland

This study aimed to assess the clinical applicability of MRI criteria for differentiation of pituitary adenomas and cystic pituitary lesions. One hundred ninety-eight consecutive patients with surgical resection of a pituitary adenoma/cystic pituitary lesion were retrospectively analyzed, blinded to clinical data and histopathological diagnosis. Different morphologic criteria were assessed: signal intensity in T2/T1w images, pattern of contrast enhancement, size, super-/infrasellar extension, and invasion of the cavernous sinus. For validation of the criteria, a second independent patient cohort (n = 102) was analyzed for diagnostic accuracy of the criteria. We identified differences between subtypes of pituitary adenomas regarding morphological MRI criteria. Especially, ACTH-producing adenomas and GH-producing adenomas showed partially specific imaging features. Application of our criteria on the second patient cohort (n = 102) did however not significantly improve diagnostic accuracy. Only differentiation between cystic pituitary lesions and adenomas was facilitated using these criteria, but did not reach statistical significance in this cohort (P = 0.352). MRI criteria might facilitate differentiation between pituitary adenomas and cystic pituitary lesions, but not between subtypes of pituitary adenomas. These subtypes show partially specific MR imaging features, however, due to a high variability knowledge of clinical symptoms and laboratory findings remain essential for the correct diagnosis.

Developmental and Functional Effects of Steroid Hormones on the Neuroendocrine Axis and Spinal Cord

This review highlights the principal effects of steroid hormones at central and peripheral levels in the neuroendocrine axis. The data discussed highlight the principal role of oestrogens and testosterone in hormonal programming in relation to sexual orientation, reproductive and metabolic programming, and the neuroendocrine mechanism involved in the development of polycystic ovary syndrome phenotype. Moreover, consistent with the wide range of processes in which steroid hormones take part, we discuss the protective effects of progesterone on neurodegenerative disease and the signalling mechanism involved in the genesis of oestrogen-induced pituitary prolactinomas.