Interstitial pulmonary disease induced by occupational exposure to paraffin.

An occupational interstitial pulmonary disease was observed in a 59-year-old workman after five years of massive exposure to aerosolized paraffin. Histologic studies of open-lung biopsy showed a lipoid pneumonia characterized by (1) alveolitis involving large lipid-laden macrophages and (2) interstitial fibrosis. Electron microscopy of AMs disclosed features of paraffin-laden cytoplasmic vacuoles. Successive treatments included prednisolone and cyclophosphamide. Despite these treatments and withdrawal from exposure, the pulmonary function became impaired progressively, resulting in restrictive syndrome and severe exertional dyspnea. Concomitantly, PMNs harvested by BAL increased, whereas initial lymphocytosis decreased. This is the first case observed of occupational interstitial fibrosis in which electron-microscopic findings clearly established a relationship with an exposure to paraffin. This observation also emphasizes the switch from alveolitis to fibrosis in the pathogenesis of interstitial pulmonary disease.