Unusual association of cervical arachnoid cyst and idiopathic intracranial hypertension.

Unusual association of cervical arachnoid cyst and idiopathic intracranial hypertension.

Arachnoid cysts (ACs) are more commonly seen intracranially rather than intraspinally, with most being asymptomatic. This case report presents a rare association between symptomatic AC and idiopathic intracranial hypertension (IIH). In a 71-year-old man who exhibited long-standing bilateral shoulder pain and severe left brachialgia despite an unremarkable physical examination. Radiologic investigations revealed a left C5-6 cervical arachnoid cyst, and during treatment, the patient was diagnosed with IIH. Surgical excision of the cyst failed, so the patient was treated with a lumbar puncture (LP) shunt that required several revisions. During these revisions, IIH was diagnosed, leading to the insertion of a ventriculoperitoneal (VP) shunt, which improved the symptoms. Early diagnosis of IIH through lumbar puncture in cases of spinal arachnoid cysts allows for earlier treatment with cerebrospinal fluid (CSF) diversion via a VP shunt, reducing repeated hospital admissions and surgical interventions.