대한흉부영상의학회 Weekly Chest Cases

Diagnosis: Pneumocystis pneumonia
Radiologic Findings: Fig 1. Chest PA shows subtle, ill-defined ground-glass opacities in the bilateral lower lung fields.
Fig 2. CT scan reveals basal-predominant multifocal ground-glass opacities with intralobular septal thickening in both lower lobes.
Fig 3. CT scan obtained 6 months before suggests increased extent of the abnormality.
Brief Review: Pneumocystis jirovicii is an atypical fungus that causes pneumonia usually in immunocompromised human hosts. On HRCT, extensive ground-glass opacity is the principal finding in pneumocystis pneumonia, reflecting accumulation of intra-alveolar fibrin, debris, and organisms. A predilection for the upper lobes has also been described. Pulmonary cysts with varying shape, size and wall thickness occur in as many as one third of patients with pneumocystis pneumonia. The incidence of pulmonary cysts has been reported to be lower in patients without HIV infection than in HIV-infected patients. Although spontaneous pneumothorax can occur in the absence of definable lung cysts, the frequency of spontaneous pneumothorax increases with when definable lung cysts present. Cysts may resolve after treatment and clearing of infection.
References: 1. Kanne JP, Yandow DR, Meyer CA. Pneumocystis jiroveci Pneumonia: High-Resolution CT Findings in Patients With and Without HIV Infection. AJR 2012;198:W555–W561.
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대한흉부영상의학회 Korean Society of Thoracic Radiology