Cerebral Schistosoma japonicum infection confirmed by histopathology and PCR: Diagnostic and therapeutic challenges in multiple parasitic coinfections.

Cerebral schistosomiasis, a rare manifestation of schistosomiasis, is challenging to diagnose due to non-specificity in the clinical and radiologic findings and cross-reactivity in serologic testing with other helminths. Coinfection with multiple parasites further complicates diagnosis and treatment. A previously healthy 32-year-old Filipino man presented with a seizure. Brain magnetic resonance imaging (MRI) revealed multiple clustered enhancing nodules with surrounding vasogenic edema in the left frontal lobe. Serologic testing was positive for anti-Schistosoma japonicum, Strongyloides, and Toxocara IgG antibodies. Follow-up MRI performed 20 days after the initial MRI demonstrated spontaneous resolution of preexisting enhancing lesions and the appearance of new non-contiguous lesions before antiparasitic therapy. Because imaging and serology analyses could not identify the causative organism, the left frontal lobe was biopsied. Histopathologic examination demonstrated schistosome eggs surrounded by granulomatous inflammation. PCR analysis of formalin-fixed paraffin-embedded tissue confirmed Schistosoma japonicum-mediated cerebral schistosomiasis. Following treatment of concomitant strongyloidiasis with ivermectin, the patient received praziquantel and corticosteroids without developing Strongyloides hyperinfection syndrome. Follow-up MRI demonstrated resolution of the cerebral lesions. To our knowledge, this case documents previously undescribed dynamic pretreatment MRI changes together with the gross intraoperative appearance of cerebral schistosomiasis. Our findings highlight the diagnostic value of histopathologic confirmation when multiple parasitic infections coexist, underscoring the importance of detecting and treating concomitant Strongyloides stercoralis infection before corticosteroid therapy.