Giemsa stain…routinely used for cytologic examination of blood (= blood film) The number of neutrophils are increased in this field…acute inflammation RBCs

Protein exudated into alveolar spaces…pink material Inflammatory cells in alveolar spaces Blood vessels in the alveolar walls are dilated bronchopneumonia

Acute inflammation transcytosis Dilated venule margination

Acute inflammation margination Dilated vessels Neutrophils + pink material (exudated proteins)

Exudate composed of pink fibrin + neutrophils…acute inflammation

Gram stain..positive cocci inside phagocytes in a background of inflammatory cells

High power of blood vessel wall showing fibrin, extravasated RBCs and neutrophils Fibrinoid necrosis (vasculitis)

Acute inflammation mainly neutrophils and some macrophages And some pink material (proteins)

Pitting edema

Congested epiglottis (laryngeal edema)

Right lung Serous pleural effusion

Serosanguinous pleural effusion

Chylous peritoneal effusion (chylous ascites) …commonly due to lymphatic obstruction due to lymphoma, TB…etc Milky (cholesterol content…etc.)

Sticky material (fibrin) …fibrinous pericardial effusion

Fibrin

Pus on colonic mucosa (infectious colitis…etc.) …suppurative inflammation

Suppurative pericardial effusion

Pus in brain coverings…suppurative inflammation (pyogenic (bacterial) meningitis)

Bronchopneumonia …like in slide 2

Gallbladder mucosa Neutrophils in mucosa …acute cholecystitis

Bronchopneumonia …like in slide 2 & 19

Abscess (liquefactive necrosis)…abscessizing pneumonia

Abscesses (abscessizing pneumonia)

Bacterial colonies neutrophils

Abscess in lung…note the disturbed alveolar architecture

Bacterial colonies neutrophils

May be benign as in peptic ulcer disease (affects duodenum mainly, or stomach, and mainly caused by H.pylori) And may be malignant (underlying cancer) Ulcer in gastric mucosa Ulcer is a disruption of whole mucosal thickness that is repaired by fibrosis. microscopically we see in the bottom collagen, in the middle granulation tissue and on the top we find fibrin, neutrophils and necrotic debris

Malignant ulcer elevated by cancer

Ulcers in larynx due to mechanical pressure by tube due to prolonged intubation for mechanical ventilation

Fibrin and necrotic debris Ulcer of squamous mucosa Granulation tissue

Remember that in DM: neuropathy (loss of pain sensation), vascular problem (ischemia) and decreased immunity…ulcers are difficult to repair Transmetatarsal amputation Skin ulcer

Below knee amputation Large ulcer with wet gangrene

endometrium Plasma cell…once you see it in endometrium it means chronic endometritis…it causes menstrual problems

Chronic inflammation under synovium and it is so severe that it forms lymphoid follicles…seen in rheumatoid arthritis (an autoimmune joint disease)

Chronic inflammatory cells in the interstitium in between the alveoli …this is chronic interstitial pneumonia

This is yellowish to whitish thickening in bronchiolar walls …this is fibrosis (the end result of chronic inflammatory conditions

This is myocardium This is area of previous infarction (necrosis due to ischemia)…now it is being repaired by granulation tissue which will be followed by fibrosis

Granulation tissue Inflammatory cells Thin-walled blood vessels fibroblast

Severe interstitial fibrosis Large area of fibrosis Distorted alveoli

Adhesions (fibrosis) between viscera Occur due to chronic infections…etc. inside abdomen Also in recurrent operations May affect mechanically the organs and cause intestinal obstruction Treated by adhesolysis

Granulation tissue Immature collagen + fibroblasts This is a closed blood vessel Re-epithelialized part of epidermis

Surrounding fibrosis (pale areas…because abscesses heal by fibrosis) An abscess (liquefactive necrosis)

Caseating necrosis in hilar lymph node

Silicotic nodule…a fibrosis nodule seen in silicosis Lung tissue

Miliary TB …when TB spreads in the lung and other organs (small granular deposits)

Caseating granuloma Caseating necrosis Epithelioid histiocytes and chronic inflammatory cells

Caseating granuloma Caseating necrosis Epithelioid histiocytes and chronic inflammatory cells

Epithelioid histiocyte

We see non-caseating granulomas in sarcoidosis…etc. They can occur in TB Langhans MNGCs can be seen in diseases other than TB …and in TB we can find foreign body-type giant cells Langhans multinucleated giant cells Non-caseating granulomas

Noncaseating granulomas in lung

Reference: WebPath