<prompt> A 45 yr old patient presents with fever, night sweats, weight loss. On X ray a mass in apical lobe of lung is seen. On histopathology found to have caseous necrosis. What is the underlying process?Enzymatic degenerationHypersensitivity reaction with modified macrophages, lymphocytes and giant cellsAcute decrease in blood supplydecreased growth factors  <response>: Ans. b Hypersensitivity reaction with modified macrophages, lymphocytes and giant cellsRef: Robbins 9thpg 208-211; 8thpg 204-208The given clinical features and radiological Findings are suggestive of Tuberculosis in which histopathology of the affected organ shows granuloma, that consists of modified macrophages, lymphocytes and giant cells. 