Isolated pulmonary microangiitis mimicking pneumonia in a patient infected with human immunodeficiency virus.

We describe the first case, to our knowledge, of apparently isolated pulmonary vasculitis mimicking bacterial pneumonia in a patient infected with human immunodeficiency virus (HIV). Patients presenting with fever, cough, and pulmonary infiltrates present a diagnostic challenge. As a result of severe T cell mediated immunosuppression and humoral dysregulation, the differential diagnosis is diverse. One must consider both noninfectious and infectious etiologies. Noninfectious etiologies such as pulmonary lymphoma, endobronchial Kaposi's sarcoma, and adverse drug reactions are common. Recent recognition of the paradoxical association between HIV and systemic vasculitis requires additional acknowledgment of this problem in diagnosis.