A 47-year-old Chinese woman living in Japan was referred with a 2-month history of cough with hemoptysis. 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) showed increased FDG uptake into a pulmonary nodular lesion 25 mm in greatest dimension in the right upper lobe, and right hilar and mediastinal lymph nodes. Laboratory investigation did not reveal either eosinophilia or a marked elevation of serum IgE titer. A culture of bronchial lavage fluid was sterile and culture for mycobacteria was negative. Cytological examination results of transbronchial brushing samples were Class III. A partial resection of the right upper lobe was performed because of the possibility of primary lung cancer. Pathological examination of the nodular lesion showed helminthic eggs surrounded by dense inflammatory infiltrates, which mainly consisted of lymphocytes and eosinophils. Based on the findings of a serological study for helminth, the morphological characteristics of the eggs and the patient's history of eating raw crab, the patient was given a diagnosis of Paragonimus westermani, which can mimic primary lung cancer.