Histopathology
Most of our cohort were diagnosed via chest imaging and with a history of known sJIA. Four patients underwent bronchoscopy and three of the four also underwent lung biopsy for further confirmation of suspected diagnosis (Table 4). Pathological findings from bronchoalveolar lavage (BAL) were mixed. Two patients showed neutrophil predominance while the remaining two patients showed macrophage/monocyte predominance. Two patients showed hemosiderin-laden macrophages and two patients showed lipid-laden macrophages on BAL. All patients were negative for bacterial, fungal, and pneumocystis-like organisms on BAL. Regarding lung biopsies, all 3 cases showed findings of mixed neutrophilic, lymphocytic, eosinophilic inflammation with cholesterol clefts or lipid laden macrophages, findings of pulmonary alveolar proteinosis, with no signs of vasculitis or capillaritis. Two cases showed alveolar and interstitial inflammatory changes consistent with chronic inflammation with pulmonary alveolar proteinosis. The third case showed an “acute patchy to diffuse bronchopneumonia,” with concern for possible lipoid pneumonia; the interpretation was complicated by an acute inflammatory process overlapping with mild chronic interstitial changes. In this patient’s case, there was a bronchoscopy with BAL after lung biopsy which demonstrated Periodic Acid-Schiff positive staining and an elevated lipid laden macrophage index concerning for pulmonary alveolar proteinosis on BAL sample.