Pancoast tumors- among the warning signs of lung cancer

Lung cancer that is growing right at the top of the lung is sometimes known as a Pancoast tumor. These tumors can cause very specific symptoms. These are among the warning signs of lung cancer. The most common is severe shoulder pain. They can also cause a collection of symptoms called "Homer's syndrome." These are:

Drooping or weakness of one eyelid
Small pupil in that eye
Loss of sweating on that same side of the face

These symptoms of Homer's syndrome are caused by the tumor pressing on or damaging a nerve that runs up from the neck to that side of the face.