(2)redhepatization:3rd-4th daysgrossthe lobe distinctly red, firm, and airless with aliver-like consistencyan overlying fibrinous or fibrinosuppurativepleuritisLMalveolar space: a flock of RBC, packed withfibrin nets which stream from one alveolusthrough the pores of kohn into adjacent alveoli,neutrophils
（2）red hepatization: 3rd-4th days gross ⚫ the lobe distinctly red, firm, and airless with a liver-like consistency ⚫ an overlying fibrinous or fibrinosuppurative pleuritis LM alveolar space: a flock of RBC, packed with fibrin nets which stream from one alveolus through the pores of kohn into adjacent alveoli, neutrophils
(3）gray hepatization: 5th -6th daygrossgray-brown and solid, liver likeconsistencyLMthe alveolar capillaries appear compressedalveolar spaces: progressive disintegration ofneutrophils along with the continuedaccumulation of fibrin
（3）gray hepatization: 5th –6th day gross gray-brown and solid, liver like consistency LM ⚫ the alveolar capillaries appear compressed ⚫ alveolar spaces: progressive disintegration of neutrophils along with the continued accumulation of fibrin
(4)resolutionstage:1 weekthe resorption of exudate and enzymaticdigestion of inflammatory debris, withpreservation of the underlying alveolarwall architectureGross softening, volumeLM WBC I fibrin absorbed
（4）resolution stage: 1 week the resorption of exudate and enzymatic digestion of inflammatory debris, with preservation of the underlying alveolar wall architecture Gross softening, volume LM WBC fibrin absorbed
Lobar pneumonia: stage of engorgement(hematoxylin-cosin)
congestion stage
congestion stage