A 72-year-old woman has had difficulty with vision in her right eye for 3 months. She also has pain in the right upper chest. The findings on physical examination include unilateral enophthalmos, miosis, anhidrosis, and ptosis on the right side of her face. A chest radiograph shows right upper lobe opacification and bony destruction of the right first rib. Which of the following conditions is most likely to be present in her?