Those that come to surgery are either very large “giant” tumors or other tumor types that produce PRL, including the rare densely granulated lactotroph tumors, acidophil stem cell tumors and immature PIT1-lineage tumors (formerly known as silent subtype 3 pituitary adenomas or poorly differentiated PIT1-lineage tumors6,23). The gene discussed is PRL; the disease is neoplasm.