Flock worker's lung - Broadening the spectrum of clinicopathology, narrowing the spectrum of suspected etiologies

Study objectives: Workers in the nylon flocking industry recently have been found to be at increased risk of chronic nongranulomatous interstitial lun g disease. Although a spectrum of cytologic and histopathologic abnormaliti es has been observed, nonspecific interstitial pneumonia, lymphoid nodules, and lymphocytic bronchiolitis predominated in the 19 previously reported c ases of flock worker's lung. Here we describe the additional patients who a ppear to expand the histopathologic spectrum and add to the evidence sugges ting a causative role for respirable-sized nylon fragments. Methods: We studied all North American patients (n = 5) found in 1998 to sa tisfy our previous case definition of flock worker's lung. Two pulmonary pa thologists independently reviewed each biopsy specimen. Results: All five patients reported cough and dyspnea, Only one patient had crackles on chest auscultation. High-resolution CT scan, interpreted with attention to subtle ground-glass attenuation, remained a highly sensitive d iagnostic test. Pulmonary function tests and plain chest radiograph were le ss sensitive. One patient's wedge biopsy showed previously described protot ypical findings, Two others had transbronchial biopsies showing some of the same features. The fourth patient's wedge biopsy showed desquamative inter stitial pneumonia, The fifth patient had bilateral synchronous adenocarcino ma but with radiographic evidence of diffuse interstitial fibrosis, These 5 patients and the 19 patients studied previously were exposed to nylon floc k manufactured by a rarely used cutting technology. Conclusion: Findings in these five patients appear to broaden the spectrum of the clinicopathology of flock worker's lung and add to the evidence incr iminating respirable-sized nylon particulates produced during the manufactu re and use of rotary-cut nylon flock.