Eosinophilic pleural effusion and presence of filariform larva of Strongyloides stercoralis in a patient with metastatic squamous cell carcinoma deposits in the pleura.

A 58-year-old, human immunodeficiency virus (HIV) negative, male farmer presented with a right-sided hemorrhagic, exudative, eosinophilic, rapidly reaccumulating pleural effusion. Pleural biopsy revealed secondary deposits from a squamous cell carcinoma. Wet mount film of pleural fluid unexpectedly showed filariform larvae of Strongyloides stercoralis. Our observation suggests that strongyloidiasis should be considered as the etiological cause for pleural effusion of obscure etiology. The threshold for suspicion should be high if the pleural effusion is exudative and eosinophil rich.