Monarch Disease Ontology identifier MONDO_0006372 (pituicytoma) is an extremely rare, WHO grade I, circumscribed and slow-growing tumor that arises from the neurohypophysis or infundibulum and described in adults. It is characterized by the presence of elongated, spindle-shaped neoplastic glial cells that form storiform patterns or interlacing fascicular arrangements. Signs and symptoms include visual disturbances, headache, amenorrhea, and decreased libido. Also known as: pituicytoma (WHO grade I), posterior pituitary astrocytoma.