Unusual presentation of hydatid cyst as primary and solitary manifestation of the disease in central nervous system: case report and literature review

Abstract

Background: Cerebral echinococcosis, caused by Echinococcus granulosus, is a rare (1–2% of cases) but severe form of hydatid disease, primarily affecting children (70–80% of intracranial cases). Cysts are typically large, solitary, and located in the supratentorial region—especially the parietal lobe—due to hematogenous spread, presenting with mass effect symptoms like focal deficits or raised intracranial pressure. Though usually solitary, multiple cysts can occur. Complete surgical removal is the treatment of choice. Given its potentially fatal course, especially in children and young adults (50–75% of cases), early diagnosis and intervention are crucial, particularly in low-resource settings.

Case Presentation: A 34-year-old man from a rural area presented with headache, left hemiparesis, and abnormal movements. Initial MRI misdiagnosed a right parietal lesion as an arachnoid cyst; subsequent imaging revealed a large cystic lesion at the right temporoparietal junction, raising suspicion for hydatid disease. Intraoperative findings and histopathology confirmed cerebral hydatid cyst due to Echinococcus granulosus. Despite intraoperative cyst rupture, complete excision was achieved. The patient received cyclic albendazole for three months with no complications. At one-year follow-up, neurological function improved (strength 4/5) and MRI showed complete resolution. This case underscores the diagnostic difficulty of cerebral hydatidosis and the efficacy of combined surgical and medical management.

Conclusion: Cerebral hydatid disease, caused by Echinococcus granulosus, is a rare (~2% of cases) but serious form of echinococcosis, usually presenting late with large, slow-growing cysts due to hematogenous spread. While liver and lung involvement is common, brain cysts—typically solitary and supratentorial—can mimic other lesions on MRI, sometimes showing atypical features like ring enhancement and edema. Serological tests have limited sensitivity in the brain; definitive diagnosis relies on histopathological confirmation of the laminated membrane or daughter cysts. Complete surgical excision without rupture (e.g., Dowling’s technique) is the cornerstone of treatment to prevent anaphylaxis and recurrence, though rupture occurs in up to 28% of cases. Adjuvant albendazole is advised, particularly post-rupture. Prognosis is favorable with timely intervention. Cerebral hydatidosis should be suspected in endemic regions when evaluating large brain cysts, even with atypical imaging.