Pituitary Lesions By John D Carmichael, MD, Keck School of Medicine of the University of Southern California Reviewed / Revised Apr 2023 View Patient Education Patients with hypothalamic-pituitary lesions generally present with some combination of Symptoms and signs of a mass lesion: headaches, altered appetite, thirst, visual field defects—particularly bitemporal hemianopia or the hemifield slide phenomenon (images drifting apart) Imaging evidence of a mass lesion as an incidental finding Hypersecretion or hyposecretion of one or more pituitary hormones The most common cause of hypopituitary or hyperpituitary secretion is a pituitary or hypothalamic tumor.