AIDS-related lymphomas (ARLs) are almost always of a non-Hodgkin's type. Typically, intraabdominal or subcutaneous lymph node groups are affected. Unusual presentations are not uncommon, however. Intrathoracic involvement occurs in 10% to 30% of AIDS patients. ARLs are extremely aggressive and generally present at advanced stages of disease. The chest radiograph demonstrates linear densities, lymphadenopathy, and pleural effusions. An unusual feature of ARLs is the presence of rapidly growing, well-defined lung nodules. Radiographic response to therapy may be extremely rapid, but the prognosis for patients with ARLs is poor.