Which of the following is true about pituitary adenomaa) Accounts for 10% of brain tumorsb) Erodes the sellar and extends into surrounding areac) Prolactinoma is least commond) It is differentiated by reticulin stain

Pituitary adenomas constitute approximate 10% of all primary intracranial neoplasms and about 1/3 to 1/2 of all suprasellar/juxtasellar masses Pituitary adenomas are classified on the basis of hormone(s) produced by the neoplastic cells detected by immunohistochemical stains. Most common pituitary adenomas are prolactinomas. Pituitary adenomas can be differentiated from hyperplasia by reticulin stain (Absence of reticulin network is seen in adenoma) Pituitary adenomas are sellar lesions but larger adenomas can extend through the diaphragm sella into the suprasellar region and compress the optic chiasm (causing visual field abnormalities) and other cranial nerves. Large adenomas can also erode the sellar turcica and extend into surrounding region (k/a invasive adenomas) More about Pituitary adenomas It is the most common cause of hyperpituitarism. Pituitary adenomas can be - functional (i.e. associated with hormone excess and their clinical manifestations) or - silent (i.e. without clinical symptoms of hormone excess. May or may not produce hormone) Prolactinomas are the most common adenomas Some pituitary adenomas can secrete two hormones - Growth hormone and prolactin being the most common combination Rarely adenomas are plurihormonal Age : usually found in adults Gender Prolactinomas have 4-5 : 1 female/male ratio GH secreting adenomas have 2:1 male predominance. Clinical signs & symptoms - occur due to hormone excess or mass effect (visual field disturbances, elevated intracranial pressure or occasionally hypopitutarism - d/t silent adenomas compressing normal pituitary) Acute hemorrhage into an adenoma causes rapid enlargement of mass and sudden clinical deterioration k/a pituitary apoplexy. Prolactinomas have a propensity to undergo dystrophic calcification, ranging from isolated psammoma bodies to extensive calcification of entire tumor mass (k/a pituitary stone)