62-year-old male smoker suffered from chronic bronchitis (specimen from autopsy).
- Lung tissue is in part destroyed by a poorly circumscribed tumor.
- In the center of the tumor residues of bronchial cartilage can be observed.
- The tumor consists of nests of loosely cohesive cells with only little cytoplasm. In between tumor cell nests a scant stroma is present.
- The nuclei are hyperchromatic, round to oval, displaying little polymorphy. Some nuclei resemble oats, thus the name oat-cell carcinoma.
- The chromatin is finely granular with small nucleoli (‘so-called salt and pepper’ aspect).
- Mitotic figures are rare but a number of pyknotic nuclei are present.
- In the periphery, the tumor infiltrates numerous lymphatic vessels and a large blood vessel.
- These tumors frequently exhibit extensive necrosis (not seen in the example shown).
- In the vicinity of the tumor the lung tissue shows emphysematous changes.
The tumor obstructed a large airway, leading to poststenotic pneumonia (see slideA