We report a case of Paragonimus westermani infection with a reticulonodular
lesion in the right lung, left pleural effusion, and a mobile subcutaneous
mass. Analyses of pleural effusion and bronchoalveolar lavage fluid (BALF)
showed marked eosinophilia and high levels of eosinophil cationic protein
and interleukin (IL)-5. Transbronchial lung biopsy revealed the presence of
pneumonia with mild eosinophilic infiltration but remarkable lymphocytic i
nfiltration. In this patient, high IL-5 levels in both BALF and pleural eff
usion could explain the remarkable eosinophilia.