A45 yr old patient present with history of fever .night sweat ,weight loss. On x Ray a mass in apical love of lung is seen.on histopathology it was found to have caseous nercrosis . What is the likely underlying process involved

Ref Robbins 9/e p272 Presence of history of fever, night sweat and weight loss with apical lesson having caseous necrosis is a pointer to the presence of tuberculosis in the patient.this is characterised by the stimulation of the macrophages to kill mycobacteria.the TH2 response leading to the formation of granuloma is a feature of type 4 hypersensitivity reaction