Presentation
Sustained a fall, hit her head. On oral anticoagulant therapy. Somnolent, reduced alertness during presentation. ?IC bleeding, fracture
Patient Data
Large, about 65 x 40 x 40 mm right frontal, inhomogeneously hyperdense collection. The lesion is seemingly extra-axial, separate from the brain parenchyma. Altogether findings are suggestive of bleeding into a pre-existing cystic lesion, likely an arachnoid cyst. Resultant midline shift, compression of ipsilateral sulci supratentorially, and compression of the right lateral ventricle, subfalcine and descending transtentorial herniation. A rim of subdural lower density collection is also visible with a maximum thickness of 15 mm, in keeping with hygroma.
Urgent neurosurgical referral and operation was undertaken. During the operation a pulsating arachnoid cyst was found, filled with hematoma. The source of the bleeding was found to be numerous smaller vessels, which were electrocoagulated and coated with surgicel. The cavity was refilled with fluid and the overlying dura and calvarium were sutured.
Follow-up CT shows marked reduction of the mass effect, the cyst is now filled with low density fluid.
Case Discussion
Previously unknown arachnoid cyst, that had a dramatic presentation following trauma.