Nontraumatic fat embolization. A rare cause of new pulmonary infiltrates in an immunocompromised patient.

Diffuse pulmonary infiltrates and hypoxemia are common in immunocompromised patients. We describe a patient with lymphoma who developed hypoxemia and diffuse pulmonary infiltrates during treatment with corticosteroids. Open lung biopsy and postmortem examination indicated that the cause of the infiltrates was nontraumatic fat embolization (NTFE). Most previous cases of NTFE have implicated a fatty liver as the source of emboli; however, this patient had no fatty changes of the liver. The diagnosis of NTFE in an immunocompromised patient is difficult to make because its distinguishing features, such as hypoxemia, petechiae, and altered mental status, are nonspecific in this setting.