What type of lung tumor is associated with compression of the sympathetic ganglion and can lead to Horner's syndrome?

A Pancoast tumor is a specific type of lung cancer that occurs at the apex of the lung and is notable for its potential to invade local structures, including the sympathetic ganglia. When this tumor affects the sympathetic chain, it can lead to Horner's syndrome, which is characterized by ptosis (drooping of the eyelid), miosis (constricted pupil), and anhidrosis (lack of sweating) on the affected side of the face. The invasion or compression of the sympathetic fibers results in these characteristic signs.

Pancoast tumors are most commonly associated with non-small cell lung cancers, particularly squamous cell carcinoma, but the crucial aspect of this question is the location and the resulting neurologic syndrome. Other types of lung cancer, such as adenocarcinoma and small cell lung cancer, do not typically result in Horner's syndrome through sympathetic chain involvement in the same way as a Pancoast tumor. Therefore, the association of the Pancoast tumor with sympathetic ganglion compression directly explains the development of Horner's syndrome, making it the correct answer.