Cavitary pulmonary nodules with systemic lupus erythematosus: differential diagnosis.

Cavitary pulmonary nodules rarely occur in patients with systemic lupus erythematosus and the lupuslike syndrome associated with mixed connective tissue disease. Although it has been suggested that such cavitary nodules represent areas of vasculitis and ischemic necrosis, five of seven occurrences of cavitary nodules in a series of six patients with systemic lupus erythematosus or mixed connective tissue disease proved to be the result of infection or pulmonary embolism. The causes in the other two cases are unknown, but no attempt was made to obtain a biopsy in either instance. It was concluded that vasculitis with ischemic necrosis is not a common cause of cavitary pulmonary nodules in patients with lupus.