The lymphoproliferative disorders represent a spectrum of lymphoid abnormalities that can involve the chest. Plasma cell granuloma, pseudolymphoma, posttransplantation lymphoproliferative disorders, lymphoid interstitial pneumonia, and lymphomatoid granulomatosis involve the pulmonary parenchyma, whereas Castleman's disease, infectious mononucleosis, and angioimmunoblastic lymphadenopathy with dysproteinemia involve intrathoracic lymph nodes. Recent immunohistochemical techniques give us a better understanding of the lymphoproliferative disorders. Clinical and radiologic features often allow differentiation of the lymphoproliferative disorders from the more common aggressive lymphomas.