This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Medicine
NOT a feature of Horner's syndrome 
Select and explain. 
A. Exophthalmos, B. Ptosis of upper eyelid, C. Miosis, D. Anhydrosis
A: Exophthalmos
Answer: A: Exophthalmos 
Explanation: (A) Exophthalmos # HORNER'S SYNDROME:> Enophthalmos, Ptosis, Miosis, & Ipsilateral loss of sweating (Anhydrosis)> Malignant pleural effusion often leads to dyspnea.> Pancoast's (or superior sulcus tumor) syndrome results from local extension of a tumor growing in the apex of the lung with involvement of the eighth cervical and first and second thoracic nerves, with shoulder pain that characteristically radiates in the ulnar distribution of the arm, often with radiologic destruction of the first and second ribs.> Often Horner's syndrome & Pancoast's syndrome coexist.