A case of cerebral sparganosis diagnosed by surgical resection and molecular analysis

Background: Sparganosis is a rare parasitic infection caused by the plerocercoid larvae (spargana) of Spirometra species. Central nervous system (CNS) involvement is uncommon; cerebral sparganosis can be particularly challenging to diagnose because its clinical presentation and imaging features often mimic those of more common parasitic infections (e.g., neurocysticercosis) or neoplastic lesions. Case Description: A 74-year-old woman with slowly progressive Alzheimer’s disease, who had undergone regular brain magnetic resonance imaging (MRI) examinations over the past three years, was incidentally found to have a slowly enlarging lesion with surrounding edema in the left frontal lobe on MRI of the brain. The lesion demonstrated calcification and radiological features atypical for a neoplastic process, thus prompting a left frontal craniotomy for diagnostic purposes. Intraoperatively, a whitish, linear structure was removed. Frozen section revealed granulomatous inflammation with parasitic structures. Molecular biological analysis identified the specimen as a Spirometra larva (Type I), confirming the diagnosis of cerebral sparganosis. Postoperatively, her baseline cognitive impairment persisted; however, follow-up MRI at 1 month demonstrated resolution of the enhancing lesion, and no new neurological deficits occurred. Conclusion: Cerebral sparganosis should be considered in the differential diagnosis of intracranial mass lesions with a tumor-like appearance. Although the diagnosis remains challenging, molecular techniques permit definitive confirmation. Surgical resection serves a dual role, facilitating both accurate diagnosis and treatment.