Human Phenotype Ontology identifier HP_0006767 (Pituitary prolactin cell adenoma) is a type of pituitary adenoma originating in prolactin secreting cells. This kind of adenoma is characterized by overproduction of prolactin, and may cause loss of menstrual periods and breast milk production in women. Also known as: Pituitary prolactinoma, Prolactin-secreting pituitary adenoma, Prolactinoma.