Metastatic Tumors to the Pituitary

Purpose To illustrate how the ophthalmologist can distinguish a metastatic tumor to the pituitary from a pituitary adenoma through clinical, particularly ophthalmic, findings. Methods We studied three patients with metastatic disease to the pituitary. One patient had a history of breast cancer without known metastatic disease, and two patients had no previous diagnosis of malignancy. We reviewed the literature with respect to signs and symptoms that may differentiate such lesions from histologically benign pituitary adenomas. Results Including our patients and the recent cases in the literature, 42% of patients with metastatic tumors had oculomotor palsies, compared with less than 5% of patients with pituitary adenomas. Of patients with metastatic tumors, 33% had diabetes insipidus, compared with 1% who had pituitary adenomas. Furthermore, with respect to differentiating a pituitary adenoma from a metastatic process, radiographic examinations were not helpful, and histopathologic examination was occasionally incorrect. Conclusion The ophthalmologist can potentially differentiate a metastatic tumor to the pituitary from a pituitary adenoma, thereby assisting in the proper treatment of patients.