[Diagnostic problems in rare types of pneumoconiosis].

The problems encountered in diagnosing the rare types of pneumoconiosis ( silicatosis other than asbestosis, aluminosis and hard metals fibrosis), result from the difficulties in realising a good occupational anamnese and from the disease pattern by itself. The classical examinations, (X-rays of the thorax and lung function measurements), are not able to detect the cause of these diseases, which are fundamentally characterised by an absence of specificity. These last years, new methods of diagnoses (angiotensin converting enzyme, gallium scan, transbronchial biopsies, mineralogical, cytological and histological examinations of the lung tissues and of the bronchial alveolar lavage) were developed and progressively introduced in the daily practice in pneumology. Only the examination of lung biopsies and of the products of bronchial alveolar lavage, in particular the mineralogical examinations, may usefully orientate the diagnosis. The bronchial alveolar lavage has the advantage of an easy repetition and of a small invasive character. Moreover this technique is of a rather low financial cost. However the results of these examinations must be interpreted with the greatest caution, in function of the complete medical and occupational data. The experience following more than 500 BAL shows that the discovery of talc and kaolin is very significant for an exposition since these minerals were never observed among not exposed subjects. The evidence of these minerals argues also for the diagnosis of talcosis or kaolinosis if there are radiological lesions that are compatible with these diseases. On the other hand a recent study suggests that the identification of multinuclear macrophages and of tungsten and/of tantalum in the bronchial alveolar lavage is pathognomonic of the pathology of the hard metals.