This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'Which of the following is true about pituitary tumor?a) It is present in 10% of brain tumors b) Erodes the sella and extends into surrounding areac) Prolactinoma is least commond) It is differentiated by reticulin stain \nSelect and explain. \nA. acd, B. abd, C. abc, D. ab', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Pituitary tumors account 10% of all intracranial neoplasms.\nThe most common pituitory tumor is adenoma arising from anterior lobe.\n\tMicroadenoma of they are less than 1 cm in diameter.\n\tMacroadenoma if they are more than 1 cm in diameter.\nMost tumors are microadenoma.\nMicroadenomas are the most common cause of hypetpituitrism.\nMost common pituitary microadenoma is prolactinoma.\nGH-secreting adenoma is the second most common.\nAs the adenomas expand, they frequently erod the sella turcica and anterior clinoid process.\nThey may compress optic chiasma and cranial nerves.\nHistologically they can be differentiated by normal pituitary by : -\n\n\nCellular monomorphism\xa0→\xa0Adenoma contains single type of cells (e.g., Lactotroph or somatotroph).\nAbsence of reticulin network\xa0→\xa0Reticulin stain negative, while normal pituitary parenchyma is positive.\n\n\nCorticotroph cell adenomas are PAS postive because of the presence of Carbohydrate in pre-opiomelanocorticotropin (POMC).\nHormone negative adenomas are called "null cell adenoma".\n\n\nThe majority of pituitary adenomas are sporadic in nature, and only 5%of cases arise as a result on an inherited predisposition.\nFour genes have been identified this far as a cause of familial pituitary adenoma : MENI,\xa0CDDIB, PRKARIA and AIP', 'role': 'assistant'}]