Although etiological diagnosis represent a major issue in occupational health, it is frequently difficult to achieve because of the concurrent effect of a multitude of both work-related and non-work-related pathogenic factors. A construction worker, exposed for over 20 years to silica and silicate dust, asbestos dust and vibrations transmitted through the hand-arm axis, complained of dyspnoea a cough and peripheral paraesthesia. Two years later he developed scleroderma-like skin lesions in the appendages, and a small-cell bronchogenic carcinoma was subsequently revealed by radiological and bronchoscopic examination. The analysis of a single case failed to provide any substantial support for the hypothesis that scleroderma and lung cancer have an occupational origin; however, we believe it is significant that occupational exposure to chemical and physical agents inhibiting the immune response is often observed in association with some kinds of immune abnormalities, such as those of scleroderma and oat-cell cancer.