pituitary tumor (Monarch Disease Ontology term MONDO_0017611) is a benign or malignant neoplasm affecting the pituitary gland. The vast majority are adenomas arising from the anterior lobe of the pituitary gland. Also known as: neoplasm of pituitary, neoplasm of pituitary gland, neoplasm of the pituitary, neoplasm of the pituitary gland, pituitary gland neoplasm, pituitary gland tumor, pituitary gland tumour, pituitary neoplasm.