Isolated pontomedullary hydatid cyst presenting with progressive bulbar and long-tract dysfunction: a case report and...

Intracranial cystic echinococcosis is rare, and primary involvement of the brainstem is exceptional. Because brainstem cystic lesions often share overlapping clinical and radiological features, preoperative diagnosis may be challenging, particularly when the lesion is deep-seated and located near critical bulbar and long-tract pathways.

A 47-year-old woman from a rural area presented with a 4-6-week history of progressive dysphagia and worsening weakness of all four limbs. Neurological examination revealed quadriparesis and lower cranial nerve dysfunction, including dysphonia, reduced gag reflex, and mild palatal asymmetry. Brain magnetic resonance imaging revealed a solitary, sharply demarcated intra-axial cystic lesion at the pontomedullary junction, with cerebrospinal fluid-like signal intensity, suppression on fluid-attenuated inversion recovery sequences, a thin regular wall, and no enhancement, mural nodule, calcification, or perilesional edema. Systemic evaluation showed no extracranial hydatid involvement. Given the epidemiological background and imaging pattern, a pontomedullary hydatid cyst was suspected. The narrow brainstem corridor made standard hydrodissection unsuitable, so, the patient underwent left lateral suboccipital craniotomy. Controlled cyst puncture and aspiration were performed to decompress the lesion, followed by meticulous microsurgical removal of the collapsed cyst wall without intradural spillage. Histopathology confirmed hydatid disease. The postoperative course was uncomplicated, with marked improvement of limb strength and marked recovery of swallowing function. Follow-up MRI showed complete excision without residual lesion, hydrocephalus, diffusion restriction, or mass effect.

Hydatid disease should be considered in the differential diagnosis of well-circumscribed, non-enhancing cystic brainstem lesions, particularly in patients from endemic settings. This case highlights the value of combining neuroimaging findings with epidemiological context to raise preoperative suspicion, and illustrates the need for individualized microsurgical planning in eloquent pontomedullary locations where standard hydrodissection may be unsafe or impractical.