A case of cutaneous paragonimiasis with pleural effusion

Background: Paragonimiasis is an infectious disease caused by Paragonimus, which persists in the lung of mammals. Infection in the skin is very rare. Results: A subcutaneous tumor with itching developed on the right lateroabdominal region of a 55-year-old man 10 days after eating fresh-water crab. It was surgically excised 2 months later. Examination of a specimen of the surgically excised tumor revealed an abscess containing many eosinophils. Parasites or other infectious organisms were not found in sections. The blood eosinophil count of the patient was elevated, and P. westermani-specific immunoglobulin G (IgG) antibody titer was strongly detected in the serum. The tumor was diagnosed as cutaneous paragonimiasis caused by P. westermani. Three months after eating the crab, a chest X-ray film showed a pleural effusion. P. westermani-specific IgG antibody was also detected in the pleural fluid. The patient was given 75 mg/kg/day of praziquantel for 3 days. The pleural effusion gradually disappeared after the medication. Conclusions: This patient had cutaneous paragonimiasis with a skin tumor that was diagnosed prior to the expression of a pleural effusion.