An International collaborative pathologic study of surgical lung biopsies from mustard gas-exposed patients

Background: Recent studies have shown strong evidence that bronchiolitis obliterans is the major long-term sequelae of exposure to sulfur mustard (SM). This study is the first to examine the histopathologic spectrum of changes in a large number of surgical lung biopsies from patients exposed to SM. Method: Fifteen patients with chronic respiratory disease from mustard gas exposure were divided into severe (6 cases) and mild exposure (9 cases). All had surgical (open or thoracoscopic) lung biopsy, pulmonary function tests (PFTs) and chest high-resolution computed tomography scan (HRCT). Result: The mean age of the cases was 43.8±9.6 (range 33-65). All patients had dyspnea and cough as the two main complaints. Only one patient was a smoker. Thirteen patients had normal PFTs, while one had obstruction and one had mild restriction. Six (66.6%) patients in the mild exposure and 3 (50%) in the severe exposure group showed evidence of more than 25% air trapping on chest HRCT. Among the mild group, 3 had features of constrictive bronchiolitis and another had features suggestive of this (bronchiolectasis and mucus stasis). The next most common finding was a mild-to-moderate chronic cellular bronchiolitis (3 patients). Two among the 6 in the severe group showed constrictive bronchiolitis and one showed features suggestive of constrictive bronchiolitis. Conclusion: We conclude that about half of patients had diagnostic constrictive bronchiolitis, or bronchiolectasis and mucus stasis consistent with more proximal luminal compromise. The fact that there were no differences between the low- and high-dose groups suggests that effects of SM are not solely dependent on the severity of exposure. The results also indicate that the diagnosis of chronic lung disease due to SM may be difficult. Surgical lung biopsy may be helpful in difficult cases, as constrictive (obliterative) bronchiolitis can be present in symptomatic patients with normal PFTs and chest HRCT.