A 65-year-old woman with ptosis, miosis, and enophthalmos has a chest x-ray showing a right upper lobe opacity. What is the most likely diagnosis?

• A. Suppurative bronchopneumonia
• B. Tuberculous bronchopneumonia
• C. Pancoast tumor
• D. Hamartoma

Answer: (C)

Horner syndrome with an apical/upper-lobe lung mass points to a Pancoast tumor. These tumors arise at the apex of the lung and characteristically invade nearby structures such as the sympathetic chain and the lower brachial plexus. Interruption of sympathetic innervation causes the triad: ptosis from loss of the superior tarsal muscle, miosis from unopposed parasympathetic activity, and enophthalmos due to sympathetic denervation. The upper-lobe location on imaging fits the tumor’s site, and these tumors are commonly non-small cell lung carcinomas in this setting. Other options don’t explain the combination of Horner’s syndrome signs with an apical lung mass—infectious pneumonias like suppurative or tuberculous bronchopneumonia lack this sympathetic disruption, and a hamartoma is typically a benign peripheral lesion without invasiveness to the sympathetic chain.