Areas of type II pneumocyte
proliferation were observed.
Cuboidal surface cells are morphologically resembling type II pneumocyte
Note background type II pneumocyte
nuclear staining for thyroid transcription factor 1 in A (circle) (original magnifications X40).
The initial underlying pathologic process in the lung from amiodarone toxicity is postulated to be a drug-induced phospholipidosis, (9) and the mechanism by which phospholipids accumulate in the cell is believed to be by inhibition of intracellular phospholipase when the drug and its metabolites are trapped in alveolar macrophages and type II pneumocyte
Histologic analysis showed that lesions were similar to those observed in humans and indicated necrotizing bronchointerstitial pneumonia with type II pneumocyte
hyperplasia, abundant fibrin, and streaming mucus in airways.
Lamellar bodies are secreted by the type II pneumocyte
and unfold to form tubular myelin and other large aggregates that are absorbed onto the hydrated inner layer of the alveoli.
In contrast, lungs involved with diffuse alveolar damage exhibit widened alveolar septa, reduced numbers of aerated airspaces, and other histologic changes of injury, including the presence of hyaline membranes lying within airspaces, and type II pneumocyte
hyperplasia (Figure 1, C through E).
Alveolar walls were thickened and showed necrosis of lining epithelium and type II pneumocyte
The renewal strategy of alveolar epithelium is different from that operating in conducting airways, with the type II pneumocyte
exerting both specialized (eg, the production of surfactant proteins) and precursor functions.
To confirm this, we used surfactant as a marker of type II pneumocyte
Cellular debris, including degenerating alveolar macrophages, sloughed pneumocytes, and cholesterol clefts, is often present, and there may be a regenerative type II pneumocyte
There is evidence that sclerosing hemangioma of the lung shows evidence of type II pneumocyte