[Lymphocytic interstitial pneumopathy and primary pulmonary lymphoma. Differential diagnosis]

Two cases of lymphoid interstitial pneumonia, diagnosed according to Liebow's criteria, are reported. In both cases an extra-thoracic lymphoma developed 3 and 6 years respectively after the interstitial pneumonia was diagnosed. Simultaneously, the radiological images of the lungs became more pronounced. Only a few similar cases have been published. This raises the question of whether lymphoid interstitial pneumonia and lymphomas are distinct entities, especially since the histological and immunopathological discriminating criteria seem to be discussed.