Round pneumonia: imaging findings in a large series of children

Abstract

Background: Although round pneumonia is a well-known clinical entity, there have been no large case reviews, with most knowledge based on case reports and small series from the 1960s and 1970s.

Objective: To review the imaging findings of a large series of children with round pneumonia.

Materials and methods: A retrospective review of radiographic and CT findings in all children reported to have round pneumonia at a large children's hospital from 2000 to 2006 was performed. Children with underlying medical conditions were excluded. Epidemiologic characteristics, radiographic and CT findings, and follow-up imaging were reviewed.

Results: The review identified 109 children (mean age 5 years, range 4 months to 19 years). Round pneumonias tended to be solitary 98% (107/109), have well-defined borders 70% (77/109), and be posteriorly located 83% (91/109), with the following lobar distribution: left lower lobe (36), right lower lobe (33), right upper lobe (28), left upper lobe (7), right middle lobe (4), and lingula (2). Round pneumonia tended to resolve on follow-up imaging (95%, 41/43) as compared to progression to lobar pneumonia (4.6%, 2/43). Three patients (2.6%, 3/112) originally suspected to have round pneumonia were later shown to have other diagnoses: cavitary necrosis in pneumonia (two) or pleural pseudocyst (one).

Conclusion: Round pneumonia occurs in young children (mean age 5 years), tends to be a solitary lesion, and is most commonly posteriorly located. Misdiagnosis of other pathology as round pneumonia is uncommon.