This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Clinical Aspects of Neoplasia, Subject name: Pathology
Most common histological form of lung Ca that metastasizes is - 
Select and explain. 
A. Squamous cell CA, B. Adenocarcinoma, C. Alveolar-carcinoma, D. Small cell carcinoma
D: Small cell carcinoma
Answer: D: Small cell carcinoma 
Explanation: Ans. is 'd' i.e., Small cell carcinoma o Small cell carcinomas are the most aggressive of lung tumors, metastasize widely and are virtually incurable by surgical means.o Small cell carcinoma is the most common type of lung cancer associated with ectopic hormone production and paraneoplastic syndrome.