Histopathology: pulmonarypathology

These presentations are to help you identify basic histopathological features. They do not contain theadditional factual information that you need to learn about these topics, or all the images from

resource sessions.This presentation contains images of basic histopathological features of various pulmonary

pathologies (anthracosis, asthma, pneumonia). Pneumonia is a good example of an acuteinflammatory process.

Before viewing this presentation you are advised to review relevant histology, relevant sections onacute inflammation and pulmonary pathology in a pathology textbook, the histopathology power

point presentation on acute inflammation, relevant lecture notes and relevant sections of ahistopathology atlas.

Copyright University of Adelaide 2011(Med 1: Anthracosis and lymphatic drainage semester 1; pneumonia: semester 2

Med 2: Asthma and pneumonia semester 2)

‘Dust’ cells (black arrows): alveolar macrophages that have phagocytosed inhaledcarbon. Similar cells containing haemosiderin pigment are seen in patients with chronicleft heart failure (heart failure cells).

‘Dust’ cells (black arrows): alveolar macrophages that have phagocytosed inhaled carbon. These cells migrate in thelymphatics and are here seen in peribronchial tissue. Aggregates of these cells are seen as black spotsmacroscopically in the lung, a feature known as anthracosis. Many travel to the local hilar lymph nodes which alsobecome black.

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Acute asthma. Low power view of a mucus filled bronchus.Green stars: cartilage. Black star: mucus. Pale blue stars: seromucous glands. Yellow star: edge of hilarlymph node. Red star: cartilage of adjacent bronchus. Dark blue star: vein

Acute asthma. Medium power view of the edge of a mucus filled bronchus.Green star: cartilage. Black star: mucus. Blue star: seromucous glands. Yellow arrow: smooth muscle. Red arrows:epithelial basement membrane. Green arrows: respiratory epithelium. Black arrow: arteriole. Pale blue arrows: dilatedvenules. Dark blue arrows: capillaries

Acute asthma. High power view of the edge of a mucus filled bronchus.Black star: mucus. Red arrows: epithelial basement membrane. Green arrows: damaged respiratoryepithelium. Yellow arrows: eosinophils

Most examples of lobar and bronchopneumonia result from bacterial infection causing acute inflammation. Theinflammatory exudate includes neutrophils, fibrin and fluid. Lobar pneumonia, low power (above). Large expanse oflung where alveoli are filled with an inflammatory infiltrate. Black arrows: dilated venules. Yellow arrows: alveolarwalls. In lobar pneumonia the alveoli of an entire lobe or the majority of a lobe is filled with inflammatory exudate andconsolidated.

In bronchopneumonia, infection and inflammation spreads from bronchi and bronchioles into adjacentalveoli. Alveolar inflammation and consolidation are thus initially patchy (low power view above) andsurround bronchioles.

In bronchopneumonia, infection and inflammation spreadfrom bronchi and bronchioles. Bronchi and bronchiolesare inflamed. High power (left image) and medium power(top image) of a bronchiole in bronchopneumonia. Blackarrows: respiratory epithelium. Black stars: neutrophils inbronchiolar lumen. Green star: dilated congested venule.Yellow arrows: dilated congested capillaries. Red arrows:epithelial basement membrane.

Most examples of lobar and bronchopneumonia result from bacterial infection causing acuteinflammation. The inflammatory exudate includes neutrophils, fibrin and fluid. On high power view above,neutrophils are seen filling the alveoli. Alveolar capillaries are dilated and congested with red blood cells.

Pneumonia, high power. Exudate filling alveolar spaces: neutrophils (black arrows), fibrin (black stars), macrophages (blue arrows)and extravasated red blood cells (yellow arrows). Note the relative sizes of cells. Neutrophils have a larger diameter than red bloodcells (and lymphocytes - not seen here) and macrophages are often larger than neutrophils. The black line marks the alveolar walls,as indicated also by the capillaries and epithelial cells (red arrows).

Pneumonia, medium power. Alveoli are filled with neutrophils and homogenous eosinophilic oedemafluid (black star).

Fibrinous exudate (black star) on a serosal surface as is often seen in lobar pneumonia (on the pleura)due to acute inflammation of the underlying alveoli. This example is from acute appendicitis. The blacklines represent the approximate location of the underlying serosal surface.

Pulmonary abscess (low power). Centrally there is necrotic debris and neutrophils (blue) with adjacenthaemorrhage (red) in surrounding lung tissue.