HISTOPATHOLOGICAL STUDIES ON RADIATION PNEUMONITIS

Journal Article · Tue Jun 25 04:00:00 EDT 1963 · Tohoku J. Exptl. Med.

DOI:https://doi.org/10.1620/tjem.80.89· OSTI ID:4069335

Namiki, T

Postmortem findings in 25 patients who had received radiotherapv for cancers of the thoracic region are reported. The local x-ray or Co/sup 60/ gamma -ray doses varied up to 30,500 rad. Several other systems of classification of radiation pneumonitis were rejected and a new scheme is proposed which classifies this disease into four types from a pathologic standpoint according to the degree of damage to tissue components: alveolar exudative type (11 cases); interstitial proliferative type (2 cases); mixed type (5 cases); and fibroatelectatic type (7 cases). The alveolar exudative type is characterized by the exudation caused by irradiation and its organization, which occur in the alveoli. This finding is predominant, and edema, hyaline membrane formation, fibrin deposition, and intra-alveolar fibrosis are observed, In the interstitial proliferative type the major finding is fibrous thickening of the interstitial tissue including the alvelolar septa; the elastic fibers degenerate and rupture. The changes of alveolar epithelium are observed in both of these types, with proliferation and bizarre changes. In the mixed type these changes exist in the same specimen. These three types can be classified into three stages; i.e., early,, middle, and late. The fibroatelectatic type represents a late stage; the lungs are atelectatic and abnormal proliferation of elastic fibers is observed in the alveolar wall which shows hyaline thickening. Macroscopically, this may be subdivided into localized and diffuse forms according to the extent of lesions. In the latter form, the whole lung becomes contracted to fist-size. Intra-alveolar edema was observed in 13 of 25 cases, frequently complicating in the early and midille stages. In seven of 25 cases, hyaline membrane formation was noted, mostly in the alveolar exudative type and only in cases with severe edema. Fibrin deposition occurred in 14 cases, mostly in alveolar exudative or mixed types. In the alveolar epithelium, regardless of the type of lesion, swelling and proliferation were both observed. Frequently, it assumed a bizarre form, the nuclei showing atypical forms and sometimes a multinuclear giant cell with two to three nuclei. The cytoplasm was darkly stained with eosin and was PAS-positive. Proliferating alveolar epithelium desquamated into the alveoli, and showed a tendency to fatty degeneration. In the late stage, a gland-like metaplasia with proliferation of alveolar epithelium was observed in six cases. Thickening of the alveolar septa was one of the most significant changes in radiation pneumonitis. Similar changes were seen in animal experiments with rats and rabbits. In these animals, however, marked changes could not be induced, which might be due to low sensitivity of endothelium of the alveolar capillary in comparison to the human. But in rabbits the same kind of changes as seen in human cases were noted in the alveolar septa in a few cases which received 10,000 r in divided doses (500 r, 20 times). This produced a marked change on the 140th day, and in an extensive area, fibrous thickening of the alveolar septa was observed, four to five times the normal thickness. In the human cases there was no difference in reactions between x-ray and Co/sup 60/ irradiation. In the pathogenesis of this disease, the increase of capillary permeability of the alveolar wall seems to play the most important role. In addition to it, the lesion is characterized by abnormal metabolism of alveolar epithelium and new growth of connective tissue. The diagnostic criteria of this disease are discussed. (BBB)

• Research Organization: Tohoku Univ., Sendai
• NSA Number: NSA-18-015889
• OSTI ID: 4069335
• Journal Information: Tohoku J. Exptl. Med., Journal Name: Tohoku J. Exptl. Med. Vol. Vol: 80
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

BIOLOGY AND MEDICINE
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FIBRIN
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METABOLISM
PROTEINS
RABBITS
RADIATION DOSES
RADIATION INJURIES
RADIOTHERAPY
RATS
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