First-time Seizure Unveils Possible Isolated Cerebral Hydatid Cyst
Maryama Mohamed, MD1, Davis Pathadan1, Elizabeth Wagman2, Shikhar Khurana1, Camilo Diaz-Cruz1, Ryna Then3, Aparna Prabhu1
1Jefferson Einstein Philadelphia Hospital, 2Sidney Kimmel Medical College at Thomas Jefferson University, 3Jefferson Einstein Hospital
Objective:
To describe the diagnostic and clinical management of a rare isolated cerebral hydatid cyst presenting as a first-time seizure.
Background:
Echinococcal infection of the central nervous system is uncommon and typically occurs secondary to hepatic or pulmonary involvement. Isolated cerebral hydatid cysts are particularly rare, comprising 0.5%-3% of all hydatid cysts and may radiographically mimic other benign cystic lesions. Diagnosis can be difficult in non-endemic areas where clinical suspicion is low and confirmatory testing is limited.
Design/Methods:
N/A 

 

Results:

A 49-year-old woman presented with a new-onset generalized seizure following a brief aura of perioral tingling. Initial head CT demonstrated a right parietal CSF-density cystic lesion without hemorrhage. MRI revealed a 5.5 cm multiloculated non-enhancing intra-axial cyst in the right parietal lobe, initially interpreted as a neuroglial or arachnoid cyst. Eosinophilia doubled from 7.2 to 14. The patient’s remote history of exposure to cattle and dogs in Cambodia prompted evaluation for parasitic infection. 

Echinococcus ELISA was positive, although Western blot confirmation was unavailable nationally. Unruptured hydatid cysts can appear non-enhancing, CSF-isointense, and without surrounding edema. Ophthalmologic examination revealed a left homonymous hemianopia. Systemic imaging identified a solitary 8 mm pulmonary nodule without hepatic lesions. Given exposure history, serology, and imaging features, an inactive cerebral hydatid cyst was deemed likely. Although surgical excision and histopathological confirmation is the gold standard for diagnosis, surgery was deferred due to rupture risk. The patient was managed conservatively with levetiracetam and remained seizure-free on follow-up 

Conclusions:

This case highlights parasitic infection as a differential diagnosis of intracranial cystic lesions, especially when there is relevant exposure history, increasing eosinophil counts, and supportive imaging findings. With rising intercontinental travel, access to confirmatory testing for tropical infections at U.S. tertiary and research centers is essential for accurate diagnosis and public health preparedness.

10.1212/WNL.0000000000217789
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