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What is Pancoast tumor and explain in detail?
A Pancoast tumor is a tumor of the apex of the lung. It is a type of lung cancer defined primarily by its location situated at the top end of either the right or left lung. It typically spreads to nearby tissues such as the ribs and vertebrae. Most Pancoast tumors are non-small-cell lung cancers.
The growing tumor can cause compression of a brachiocephalic vein, subclavian artery, phrenic nerve, recurrent laryngeal nerve, vagus nerve, or, characteristically, compression of a sympathetic ganglion (the stellate ganglion), resulting in a range of symptoms known as Horners syndrome.
Pancoast tumors are named for Henry Pancoast, an American radiologist, who described them in 1924 and 1932.

Signs and symptoms
Aside from constitutional symptoms of cancer such as malaise, fever, weight loss and fatigue, Pancoast tumor can include a complete Horners syndrome in severe cases: miosis (constriction of the pupils), anhidrosis (lack of sweating), ptosis (drooping of the eyelid), and pseudoenophthalmos (as a result of the ptosis). In progressive cases, the brachial plexus is also affected, causing pain and weakness in the muscles of the arm and hand with a symptomatology typical of thoracic outlet syndrome. The tumor can also compress the recurrent laryngeal nerve and from this a hoarse voice and "bovine" (non-explosive) cough may occur.In superior vena cava syndrome, obstruction of the superior vena cava by a tumor (mass effect) causes facial swelling cyanosis and dilatation of the veins of the head and neck.A Pancoast tumor is an apical tumor that is typically found in conjunction with a history of smoking tobacco