Pancoast (superior sulcus) tumour

A Pancoast or superior sulcus tumour is defined by where it is rather than by what it is: it is a lung cancer, usually non-small-cell, arising in the apex of the lung and invading the structures of the thoracic inlet. It is a presentation and a location, not a tumour entity in the WHO classification, which is why this corpus records it as a term rather than as a cancer page. The syndrome comes from what it invades: the lower brachial plexus, giving pain in the shoulder radiating down the inner arm to the fourth and fifth fingers with weakness and wasting of the hand; the sympathetic chain, giving Horner's syndrome, a drooping eyelid, a constricted pupil and loss of sweating on that side of the face; and sometimes the first ribs and vertebral bodies. Because the chest X-ray shadow sits at the apex behind the clavicle it is easy to miss, and because the symptoms are musculoskeletal these tumours are commonly managed as shoulder problems for months before a scan is done. MRI, not CT, is the test NICE NG122 names for assessing the extent of disease in superior sulcus tumours, because it shows plexus and vertebral involvement that CT does not. Treatment is a separate question from where it sits in the classification and is carried by the non-small-cell pages.