This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory Radiology, Subject name: Radiology
A 75-year-old male presented with chief complaint of pain in the right shoulder. CXR is shown below. Which of the following could be the cause of pain in this patient? 
Select and explain. 
A. Pancoast tumor, B. Sarcoidosis, C. Subclan aery aneurysm, D. Mesothelioma
A: Pancoast tumor
Answer: A: Pancoast tumor 
Explanation: CXR shows a mass in the right lung apex and there is associated destruction of the right 2nd and 3rd ribs posteriorly. A combination of an apical mass along with the destruction of the rib is characteristic of Pancoast tumor/ Superior Sulcus Tumor. MRI is a more sensitive investigation in identifying the extension of tumor into adjacent soft tissue and bone.