Pulmonary vascular involvement in sarcoidosis: granulomatous angiitis and microangiopathy in transbronchial lung biopsies

Summary To evaluate the occurrence of granulomatous angiitis and microangiopathy in the lung with sarcoidosis, transbronchial lung biopsy specimens were examined from 174 cases with sarcoidosis. Granulomatous angiitis was seen in 72 cases, which corresponded to 53% of the cases with granulomata. Granulomatous angiitis showed venous involvement (65%), both venous and arterial involvement (24%) or arterial involvement only (11%). There was no significant difference in occurrence of granulomatous angiitis between upper and lower lobes. The cases with granulomatous angiitis in the lung had a higher frequency of ophthalmic symptoms and elevated serum angiotensin converting enzyme level. Basal lamina layering in the microvasculature was more often observed in the bronchial mucosa than in the alveolar walls and is not exclusively related to granulomata. Endothelial proliferation and basal lamina alterations in granulomatous angiitis may be closely associated with granulomas. The present study revealed coexistence of granulomatous angiitis and microangiopathy in the lung with sarcoidosis and suggests that both may participate in the development of pulmonary sarcoidosis.