[Bronchiolo-alveolar carcinoma complicating myasthenia treated by azathioprine]

We report a case of broncho-alveolar carcinoma (CBA) in a man of 64 who had been treated with azathioprine for severe myasthenia gravis. The myasthenia was characterized by predominant involvement of the respiratory muscles, by resistance to anticholinesterase and by association with a thymoma without improvement after thymectomy. The CBA was associated with alveolar haemorrhage (HA) confirmed by lung biopsy and also by an infection due to Mycobacterium chelonae. The occurrence of HA in an immunodepressed patient is often due to an infection, notably aspergillosis. The role of CBA and the mycobacterial infections in the pathogenesis of HA is discussed. The use of azathioprine may lead to the occurrence of cancers, notably lung cancers, and also to haemopoietic neoplasia when doses of greater than 50 grams are used. We think that azathioprine may have contributed to the genesis of CBA in our patients.