Pneumocystis carinii pneumonia with an atypical granulomatous response

Pneumonia due to Pneumocystis carinii may present atypical radiographic and pathologic findings. We report the case of a 32-year-old man with acquired immune deficiency syndrome (AIDS) whose chest roentgenogram showed a bilateral diffuse nodular pattern suggestive of miliary tuberculosis. Diagnosis ultimately required open lung biopsy, which showed evidence of an atypical granulomatous reaction with Pneumocystis carinii in the absence of other organisms. P carinii pneumonia must be considered in the differential diagnosis of patients with AIDS with nodular pulmonary densities and evidence of an atypical granulomatous reaction on pathologic specimens.