Inflammatory Pulmonary Nodules in Kawasaki Disease

Significant pulmonary manifestations of Kawasaki disease (KD) are uncommon. However, epidemiologic data from KD epidemics reveal an association between KD and a recent respiratory illness, and peribronchial cuffing or interstitial infiltrates have been reported on chest X-rays in 15% of acute KD patients. Moreover, pneumonia has been documented in 86% of autopsied acute stage cases. We report two children with KD in whom pulmonary nodules developed. The first was a 4-month-old boy with fatal acute KD. This patient had symptoms of cough and nasal congestion, and autopsy revealed inflammatory nodules in the lung as well as large coronary artery aneurysms. The second patient was a 6-month-old boy with atypical KD complicated by a coronary aneurysm in whom three peripheral pulmonary nodules were noted on chest Xray and confirmed by chest CT scan. One nodule was biopsied, revealing a non-encapsulated fibrovascular nodule infiltrated by numerous mononuclear cells. The patient was treated for KD with intravenous gammaglobulin and aspirin therapy, and did well. To characterize further the histologic features and inflammatory component of these nodules, immunohistochemistry was performed on tissue sections using antibodies to common leukocyte antigen (LCA) and Factor VIII-related antigen. In both cases, there was marked LCA positivity within the lesions indicating the presence of inflammatory mononuclear cells, and marked Factor VIII-related antigen positivity within and around the nodules, indicating extensive angiogenesis. We propose that there is a spectrum of severity of pulmonary involvement in KD, ranging from subclinical or symptomatic interstitial micronodular infiltrates to larger inflammatory pulmonary nodules. These infiltrates and nodules are likely a host response to the etiologic agent and may resolve with the disease process. Recognition of this pulmonary complication of KD may enable cautious observation of such lesions for spontaneous resolution; biopsy may be unnecessary unless the lesions persist after acute KD has resolved.