Pancoast’s syndrome /pan″cōsts/ [Henry K. Pancoast, American radiologist, 1875–1939] , 1. a combination of signs associated with a tumor in the apex of the lung. The signs include neuritic pain in the arm, atrophy of the muscles of the arm and the hand, and Horner’s syndrome and are caused by the damaging effects of the tumor on the brachial plexus and sympathetic ganglia. 2. an abnormal condition caused by osteolysis in the posterior part of one or more ribs, sometimes involving associated vertebrae.
