A solid, low grade, spindle cell, glial neoplasm of adults that originates in the neurohypophysis or infundibulum. Clinical signs and symptoms include visual disturbance, headache and features of hypopituitarism. Pituicytomas are well-circumscribed, solid masses that can measure up to several centimeters. Histologically, they show a compact architecture consisting of elongate, bipolar spindle cells arranged in interlacing fascicles or assuming a storiform pattern. [from
HPO]