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Angiomatous lesions in the wall of chronic pyothorax
1Department of Surgery, National Kinki Central Hospital for Chest Diseases, Sakai, Japan.
Insights
Massive hematoma in chronic pyothorax (CP) may stem from vascular lesions. Angiomatous lesions in the CP wall appear to precede intrapleural bleeding and subsequent hematoma formation.
Area of Science:
- Thoracic Surgery
- Pathology
- Pulmonary Medicine
Background:
- Massive hematoma formation within chronic pyothorax (CP) cavities is a known complication.
- The underlying mechanism driving this complication has remained largely unclear.
Purpose of the Study:
- To investigate the histological characteristics of chronic pyothorax walls.
- To elucidate the vascular mechanisms potentially leading to hematoma formation in CP.
Main Methods:
- Histological examination of 99 chronic pyothorax wall specimens.
- Immunohistochemistry was utilized to analyze vascular lesions.
- Cases were categorized into groups based on specific histological findings.
Main Results:
- Angiomatous lesions were identified at the fibrin-fibrous layer junction in 33 cases (Group I).
- Dilated vessels bulging into the pleural cavity were noted in Group I.
- Two cases (Group II) exhibited features resembling arteriovenous fistulas; 7 showed necrosis; 57 were Group III.
Conclusions:
- The findings suggest that the development of angiomatous lesions precedes intrapleural bleeding.
- These vascular abnormalities are implicated as a potential cause of massive hematoma in chronic pyothorax.
Abstract:
Formation of massive hematoma in the cavity of chronic pyothorax (CP) has been described previously, but its mechanism remained unclear. In the present study of 99 cases, the vascular lesions in the wall of CP were examined by histological methods, including immunohistochemistry. The age of patients ranged from 42 to 80 years (mean 57 years), with a male to female ratio of 3.3. Histologically the CP wall was covered by a fibrin layer containing cellular debris and red blood cells. Directly beneath the fibrin layer, a fibrous layer of varied thickness was present that extended to the subserosal tissue or so-called fat plane defined by computed tomography. At the junctional region between the fibrin and fibrous layer, angiomatous lesions were observed in 33 cases (Group I). In the fibrin layer of this group, dilated vessels frequently bulged into the pleural cavity. In another two cases, closely packed large vessels with irregularly thickened walls resembled an arteriovenous fistula (Group II). In seven patients, histologic specimens showed a total necrosis. The remaining 57 cases without the findings in Groups I and II were categorized as Group III. These findings suggested that formation of angiomatous lesion preceed intrapleural bleeding, which occasionally progressed to form a massive hematoma.