A case of cerebral paragonimiasis misdiagnosed as eosinophilic granulomatosis with polyangiitis.

Paragonimiasis is a parasitic disease caused by Paragonimus westermani infection, and migration to the brain results in cerebral paragonimiasis. Cerebral paragonimiasis is now extremely rare, but a few cases are still reported. A 48-year-old Japanese woman presented with right-hand convulsion, right-hand numbness, sputum, and fatigue. Chest computed tomography demonstrated multiple nodular lesions, and head computed tomography revealed a hemorrhagic lesion in the left motor cortex. Magnetic resonance imaging revealed multiple small ring-shaped lesions with surrounding edema. Laboratory evaluation demonstrated peripheral eosinophilia. We considered eosinophilic granulomatosis with polyangiitis and started steroid treatment as a diagnostic therapy since we wanted to avoid cerebral lesion biopsy if possible. However, the patient underwent craniotomy surgery after steroid treatment for four months because a new intracerebral mass lesion had appeared. Trematode eggs were detected in the sample, and the final diagnosis was cerebral paragonimiasis. The patient was successfully treated with praziquantel. Cerebral paragonimiasis is extremely rare but should be considered in the differential diagnosis if atypical intracranial hemorrhage and peripheral eosinophilia are observed.