[A case of occupational lung disease (welder lung) in a mechanical worker].

A case of welder's lung is reported in a male hard smoker who had worked as welder-carpenter for almost 30 years. In order to establish an etiologic diagnosis, given the informed consent from the worker, open lung biopsy was performed that allowed to obtain sufficiently large specimens of affected lung to make histological, immunohistochemical and mineralogical examination. In such a way the pathologic features were accurately defined and a multidisciplinary approach was applied to differential diagnosis. The worker is recommended to undergo a strict health surveillance because of the reported association of welder's lung with lung cancer, especially in smokers.