This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Imaging of Lung Nodules and Masses, Subject name: Radiology
Golden S sign is seen in: 
Select and explain. 
A. Bronchogenic carcinoma with collapse of lung, B. Traction Bronchiectasis with apical scarring, C. Emphysema with increased lucency and flattened diagphragm, D. Pulmonary edema
A: Bronchogenic carcinoma with collapse of lung
Answer: A: Bronchogenic carcinoma with collapse of lung 
Explanation: Ans. (a) Bronchogenic carcinoma with collapse of lung* The Golden S sign (reverse S sign of Golden.) is seen in PA chest radiographs with right upper lobe collapse.* It is caused by a central mass obstructing the upper lobe bronchus and should raise suspicion of a primary bronchogenic carcinoma.* The right upper lobe appears dense and shifts medially and upwards with a central mass expanding the hilum. The combination of two changes together form a reverse S shane.