Nodular or Round Pneumonia With Highly Elevated Rheumatoid Factors

Abstract

Community-acquired pneumonia (CAP) chest film findings depend, in part, on the pulmonary pathogen. The typical or atypical CAPs chest film findings are rarely nodular or round. "Round pneumonias" may be infectious or noninfectious. The causes of noninfectious round pneumonias include sarcoidosis, bronchogenic carcinomas, and Wegener granulomatosis. The most common infectious CAP causes of nodular infiltrates are Q fever and Legionella micdadei. As in this case, extrapulmonary laboratory findings often provide key clinical diagnostic clues. We present an unusual case of unilateral round pneumonia most likely due to Wegener granulomatosis, and the key diagnostic clue was highly elevated rheumatoid factor levels.