Round pneumonia in an elderly woman.

KEY CLINICAL MESSAGE: We describe a case of pneumococcal round pneumonia in an elderly smoker and it demonstrates the role of inflammatory biomarkers and follow-up imaging in ruling out more ominous diagnoses.

Case

A 74-year-old smoker female presented with dry cough and shortness of breath. Physical examination identified right lung base crackles. The patient's white blood cell counts were 11,700/μL. Plain chest radiograph revealed right base infiltrate. A computed tomography (CT) scan of the chest is shown (Fig.1A and B).

Figure 1

(A and B) Computed tomography (CT) scan cross sections showing round consolidation with air bronchogram.

What is the diagnosis?

Answer: Round pneumonia.

Explanation:

The patient's blood cultures were negative, but serum procalcitonin level was elevated and urine pneumococcal antigen was positive. The patient's infection resolved with antibiotic therapy (Fig.2).

Figure 2

Follow-up CT scan cross section showing near-complete resolution of the consolidation. The test was carried out 8 weeks later.

Round pneumonia is rarely seen in adults because of the development of collateral airways (pores of Kohn and canals of Lambert) by the age of eight [1]. It is a well-defined round consolidation that tends to occur in the upper segments of the lower lobes. Round pneumonia is mostly solitary (98%) and cavitation is not a common feature [2]. Streptococcus pneumoniae is the most common culprit in children and Coxiella burnetii and Legionella micdadei are commonly seen in adults [1]. Differential diagnoses include fungal and mycobacterial infections, round atelectasis, plural fibroma, bronchogenic cyst, pulmonary pseudotumor, and malignancy [1].