[Pulmonary mucosa-associated lymphoid tissue lymphoma in a patient with myasthenia gravis].

Mucosa-associated lymphoid tissue lymphomas are a subgroup of non-Hodgkin's lymphoma. The lung is the most frequent non-gastrointestinal organ they affect. Pulmonary mucosa-associated lymphoid tissue lymphoma usually appears as a solitary mass often accidentally discovered on chest radiography. Diffuse, bilateral involvement is rare. The association of mucosa-associated lymphoid tissue lymphoma with autoimmune diseases has been reported, and a pathogenetic role has been suggested for the autoimmune process in its development. Optimum management has not yet been standardized. The case described here is a mucosa-associated lymphoid tissue lymphoma with multiple, unusually large opacities involving both lungs. The patient, a 55-year-old woman, also suffered from myasthenia gravis, an autoimmune disease characterized by an autoaggressive process against the acetylcholine receptors. Whereas other autoimmune diseases such as rheumatoid arthritis, polymyositis, and fibrosing alveolitis have been correlated with mucosa-associated lymphoid tissue lymphoma, an association between this lymphoma and myasthenia gravis has not yet been reported. Complete resolution of the pulmonary opacities was obtained with cyclophosphamide treatment. It continues at 15 months after the suspension of therapy.