62-year-old male with chronic alcoholism, dilapidation, poor nutritional state and productive coughing succumbs to pneumonia (autopsy specimen).
- Coalescing eosinophilic areas of caseating necrosis of different sizes.
- Caseous areas walled off by epitheloid histiocytes and Langhans’giant cells, the latter exhibiting a horse-shoe like arrangement of nuclei. Epitheloid histiocytes represent activated monocytes, Langhans giant cells arise by fusion of macrophages.
- In addition, small granulomas are observed which exhibit a comparable architecture with a central caseating area walled off by epitheloid histiocytes.
- In addition, lung tissue with signs of acute congestion. Some alveolar spaces filled with neutrophils (foci of bronchopneumonia).
Cavitation leads to spread of the disease along airways with formation of satellite lesions. These may coalesce and thus in involve large pulmonary segments (tuberculous pneumonia).
(See also slide A
IV 15 )