Isolated cerebellar hydatid cyst in a child: a rare case report.

Introduction: Hydatid disease is a parasitic infection caused by Hydatid disease, most commonly involving the liver and lungs. Intracranial hydatid cysts are rare, representing only 1-2% of cases, and posterior fossa localization is exceptional. Case presentation: We present a 7-year-old girl with a 1-month history of headache, 1 week of fatigue, and 3 days of vomiting and fever. Examination revealed lethargy and a thready pulse. MRI and CT showed a retrocerebellar cyst compressing the cerebellum with obstructive hydrocephalus. Emergency craniotomy was performed, and the cyst was excised intact. Histopathology confirmed a hydatid cyst. The patient recovered well and was discharged without complications. Discussion: Posterior fossa hydatid cysts are exceedingly rare and often misdiagnosed as more common pediatric cystic lesions. Imaging can strongly suggest the diagnosis, but histopathological confirmation remains the gold standard. Surgery is the treatment of choice, with intact excision being essential to prevent recurrence and dissemination. Our case demonstrates the diagnostic challenge and emphasizes the importance of early suspicion in endemic regions. Conclusion: Although rare, cerebellar hydatid cysts should be considered in the differential diagnosis of pediatric posterior fossa cystic lesions in endemic areas. Early recognition, accurate imaging, and meticulous surgery are key to favorable outcomes.