Abstract
Open lung biopsy specimens obtained from patients with sarcoidosis (Sar, n=17), chronic beryllium disease (CBD, n=6) and hypersensitivity pneumonitis (HP, n=5) were studied histopathologically. In HP thoracotomy was performed between 1.5 to 3 months from the onset of symptoms without previous steroid treatment.
Histological findings were as follows:
1) Non-necrotizing epithelioid cell granulomas were seen in 15 patients (88%) of Sar, 6 patients (100%) of CBD and 5 patients (100%) of HP.
2) Major pulmonary lesions of Sar and CBD were interstitially distributed non-necrotizing epithelioid cell granulomas, whereas those of HP were predominantly centrilobular lesions composed of bronchiolitis and mural and luminal alveolitis.
3) In HP, the granulomas were non-necrotic. In Sar, a few granulomas showed minimal necrosis. Generally the granulomas in Sar and HP measured up to 300 microns in diameter. In 4 patients with CBD, some granulomas measured up to 1.5mm in diameter with central hyalinization and necrosis.
4) In Sar, epithelioid cell granulomas were seen in the visceral pleura in 5 patients (29.4%) and in the interlobular connective tissue in 3 patients (17.6%). Two patients (33%) with CBD showed epithelioid cell granulomas in the interlobular connective tissue. By contrast, no patients with HP showed granulomas in the visceral pleura or in the interlobular connective tissue.
5) Granulomatous involvements of the vascular wall (granulomatous angiitis) were seen in 9 patients (53%) with Sar (4 with only PV involvement, 3 with PV and PA involvement and 2 with only PA involvement), whereas no patients with HP showed such lesions (p<0.05). In CBD, 3 patients (50%) showed granulomatous angiitis (2 with only PV involvement and 1 with PV and PA involvement).
6) Bronchiolar lesions of Sar were narrowing of the lumen or disruption of the basement membrane due to the presence of granulomas in the subepithelial layer, while those of CBD were less extensive than in Sar. In HP bronchiolar lesions were marked with intraluminal cellular infiltration and, in 3 patients (60%), intrabronchiolar polypoid organizing exudates.
7) Masson bodies were seen in 5 patients (100%) with HP, whereas they were not found in Sar or CBD (p<0.01). One patient with HP showed epithelioid cell granulomas embedded in two Masson bodies.
8) Mural and luminal alveolitis mainly composed of lymphocytes and macrophages were most marked in HP. In 5 patients (29%) with Sar, 4 patients (67%) with CBD and 4 patients (80%) with HP, there were epithelioid cell granulomas in alveolar spaces. In 3 patients with HP there were numerous macrophages with prickly cytoplasmic processes (prickly alveolar macrophages) in alveoli adjacent to centrilobular lesions. In 3 patients (60%) with HP, there were foamy cells in alveoli adjacent to bronchioles.
From the pathological viewpoint of the open lung biopsy specimens HP could be differentiated from the pulmonary pathology of Sar or CBD. Pulmonary pathology and possibly pathological processes of Sar were considered to be similar to those of CBD rather than those of HP.
