Adult-onset Still disease (AOSD) is an uncommon inflammatory condition of unknown origin and pathogenesis. Pulmonary involvement is rare and includes pleuritis and transient radiological infiltrations. We report two cases of AOSD characterized by lung involvement at presentation. Both were misdiagnosed as pneumonia with para-pneumonic effusion. We also discuss the difficulties in diagnosis of AOSD with pulmonary infiltration.Keywords: Adult-onset Still Disease; Pneumonia; Misdiagnosis.
