An unusual case of basilar artery aneurysm presenting with spastic quadriparesis.

Unruptured aneurysm usually presents with headache and neuro-ophthalmic features; when it ruptures, it presents with subarachnoid haemorrhage. Basilar artery aneurysm represents only 3-5% of cerebral aneurysms. Non-haemorrhagic symptoms and the signs of unruptured aneurysms are manifested as mass effect, thromboembolic phenomenon or epileptical attacks. Clinical presentation of unruptured aneurysm depends on structures which are involved. In our case, the patient had insidious onset headache and spastic quadriparesis with sixth cranial nerve palsy, which implicate involvement of corticospinal pathways at the level of pons.