Unusual cause for unilateral headache: a quadrigeminal cistern arachnoid cyst.

Dear Editor, Young adults are frequently presented with headaches due to various causes. Atypical facial pain, renamed as persistent idiopathic facial pain (PIFP) is a poorly understood condition with the pain described as a persistent facial pain that does not have the characteristics of cranial neuralgias and which is not attributable to another disorder.1 PIFP must be differentiated from other causes of headaches like migraine, trigeminal neuralgia (TN), cluster headache and temporomandibular joint syndrome.2 TN which classically presents as severe, short-lasting and lanciating pain over the distribution of the fi fth cranial nerve is the most common syndrome to be distinguished from PIFP. The most common causes of TN compression of the fi fth nerve by a vascular loop at the root entry zone are cerebellopontine angle epidermoids, multiple sclerosis and tumours.3 TN has also been associated with quadrigeminal and prepontine cystcausing ipsilateral or contralateral symptoms.4