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The pituitary gland is divided into two lobes, the anterior lobe (which accounts for two thirds of the volume of the gland), and the posterior lobe (one third of the volume) separated by the pars intermedia. [8] The posterior lobe (the neural lobe or neurohypophysis) of the pituitary gland is not, despite its name, a true gland.
Hyperpituitarism is a condition due to the primary hypersecretion of pituitary hormones; [3] [medical citation needed] it typically results from a pituitary adenoma.In children with hyperpituitarism, disruption of growth regulation is rare, either because of hormone hypersecretion or because of manifestations caused by local compression of the adenoma.
Pituitary tumors often encroach upon the middle chiasm from below. Pituitary apoplexy is one of the few acute chiasmal syndromes. It can lead to sudden visual loss as the hemorrhagic adenoma rapidly enlarges. The embryonic remnants of Rathke's pouch may undergo neoplastic change called a craniopharyngioma. These tumors may develop at any time ...
An adenoma is a benign tumor of epithelial tissue with glandular origin, glandular characteristics, or both. Adenomas can grow from many glandular organs, including the adrenal glands, pituitary gland, thyroid, prostate, and others.
A prolactinoma is a tumor of the pituitary gland that produces the hormone prolactin.It is the most common type of functioning pituitary tumor. [1] Symptoms of prolactinoma are due to abnormally high levels of prolactin in the blood (hyperprolactinemia), or due to pressure of the tumor on surrounding brain tissue and/or the optic nerves.
Pituitary adenomas are tumors that occur in the pituitary gland, and account for about 15% of intracranial neoplasms. They often remain undiagnosed, and are often an incidental finding during autopsy. Microadenomas (<10mm) have an estimated prevalence of 16.7% (14.4% in autopsy studies and 22.5% in radiologic studies). [10] [11]
The pituitary gland or hypophysis is an endocrine gland in vertebrates. In humans , the pituitary gland is located at the base of the brain , protruding off the bottom of the hypothalamus . The human pituitary gland is oval shaped , about 1 cm in diameter, 0.5–1 gram (0.018–0.035 oz) in weight on average, and about the size of a kidney bean .
A CT or MRI of the pituitary may also show the ACTH-secreting tumor if present. However, in 40% of Cushing's disease patients MRI is unable to detect a tumor. [8] In one study of 261 patients with confirmed pituitary Cushing's disease, only 48% of pituitary lesions were identified using MRI prior to surgery.