Spontaneous Arachnoid Cyst Rupture with Subdural Hygroma in a Child.

Arachnoid cyst of the brain is common in children but its association with spontaneous subdural hygroma is rare. A case of a nine-year-old boy, without any preceding history of trauma, is presented here who came to the emergency department of a tertiary care hospital with complaints of headache, nausea, and vomiting for the last two weeks but more for the last two days. Examination showed a young, fully conscious oriented boy with positive Cushing's reflex and papilledema of left eye. MRI (magnetic resonance imaging) of the brain showed left temporal extra-axial cystic lesion of 5.40 × 4.10 cm in size, representing arachnoid cyst, with bilateral frontoparietal subdural hygromas. Cyst was partially drained through left temporal craniectomy and subdural hygromas were drained through bilateral frontal burr holes. Postoperatively the child recovered uneventfully and was discharged on the seventh postoperative day. Histopathology proves it to be arachnoid cyst of the brain with subdural CSF (cerebrospinal fluid) collection or hygroma.