This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
Apical lung carcinoma commonly manifests as:September 2009 
Select and explain. 
A. Pleural effusion, B. Pericardial involvement, C. Homer's syndrome, D. Tumour obstruction of the airway
C: Homer's syndrome
Answer: C: Homer's syndrome 
Explanation: Ans. C: Homer's syndromeThe bulk of a true Pancoast tumor is extrathoracic, originating in an extreme peripheral location with a plaque like extension over the lung apex and principally involving the chest wall structures rather than the underlying lung parenchyma. Bronchogenic carcinomas occurring in the narrow confines of the thoracic inlet invade the lymphatics in the endothoracic fascia and include, by direct extension, the intercostal nerves, the lower roots of the brachial plexus, the stellate ganglion, the sympathetic chain, and adjacent ribs and veebrae.Carcinomas in the superior pulmonary sulcus produce Pancoast syndrome, thus causing pain in the shoulder and along the ulnar nerve distribution of the arm and hand. (These carcinomas also cause Horner syndrome.) These apical lung tumors tend to be locally invasive early.