Round pneumonia

Clinical History

A previously-well child presented with poor feeding, fever, tachypnoea and cough of 2 days' duration.

Imaging Findings

A previously-well child presented with poor feeding, fever, tachypnoea and cough of 2 days' duration. Chest x-ray showed a well-defined rounded opacity in the left lower zone, which did not obscure the left heart border, localising it to the left lower lobe. A diagnosis of round pneumonia was made and antibiotic therapy commenced. The child made a rapid and complete recovery.

Discussion

Acute pneumonia in children may produce a rounded or spherical density on chest radiographs, often termed 'round pneumonia'. This manifestation is found almost exclusively in children of less than 8 years of age. The typical clinical presentation is with an acute febrile illness, respiratory distress and cough. The cause is almost always bacterial, usually pneumococcal or staphylococcal in origin and the round shape is thought to be a result of centrifugal spread of the multiplying organisms through the pores of Kohn and the channels of Lambert. The opacities are almost always posterior and often located in a lower lobe. Initially the lesions are well defined, but lose definition and then clear rapidly with appropriate antibiotic therapy. An air-bronchogram is seen in approximately 20% of cases of round pneumonia. Radiographically, round pneumonia may mimic a primary or metastatic lung tumour, or a posterior mediastinal mass e.g. neuroblastoma. In the setting of an acute febrile illness with respiratory symptoms an infectious aetiology is much more likely and this should prompt appropriate treatment without unnecessary investigations for neoplasm. Round pneumonia in the older child or adult suggests immunodeficiency or an atypical pathogen such as a fungus.

Differential Diagnosis List

Final Diagnosis

Round pneumonia

URL:	https://www.eurorad.org/case/1556
DOI:	10.1594/EURORAD/CASE.1556
ISSN:	1563-4086