Immunoblastic lymphoma arising in chronic lymphoid hyperplasia of the pulmonary interstitium.

Chronic pulmonary lymphoid hyperplasia occurs alone or is associated with a variety of disorders of the immune system. It may be a diffuse or localized process and has been referred to as lymphoid interstitial pneumonitis or pseudolymphoma, respectively. Chronic lymphoid hyperplasia in other organs has been followed by the development of malignant lymphoma, particularly when associated with disorders of the immune system. This report describes two patients with chronic hyperplasia of the pulmonary interstitial lymphoid tissue who had malignant lymphoma, immunoblastic type found at autopsy. Long-term steroid usage in one patient suggests the possibility that immunosuppressive therapy may increase the risk of developing malignant lymphoma in patients with chronic pulmonary lymphoid hyperplasia.