<prompt> True about lung carcinoma -More than 75 of lung cancers are squamous cell typeOat cell carcinoma frquently show cavitationLung calcification is characteristically seen in oat cell carcinomaOat cell carcinoma is commonly associated with bilateral hilar lymphadenopathy  <response>: Ref:Textbook of pathology Harsh mohan 6th edition,page no.500 Oat cell carcinoma is composed of uniform, small cells, larger than lymphocytes with dense, round or oval nuclei having diffuse chromatin, inconspicuous nucleoli and very sparse cytoplasm oat a form of grain. These cells are organised into cords, aggregates and ribbons or around small blood vessels forming pseudorosettes.Theyare commonly associated with bilateral hilar lymphadenopathy. 