Trigeminal neuralgia (TN) or Tic Doloureux or prosopalgia is a neuropathic disorder of the trigeminal N that causes episodes of intense pain in the eye, lip, nose, head & jaw. TN usually develop after the age of 50 years, reported case patient with 28 years old female, complaining from severe lancinating intermittent pain, not relived by tegretol, caused by CPA arachnoids cyst which causes pressure on trigeminal ganglia in the pons, Treatment: tegretol 100mg 1x3 to relieve sever lanceting pain the pain is not response to the medication and finally we decided to do ARhizotomy or neurectomy to the trigeminal nerve ending put the patient refuse the treatment Discussion: Any case of TN which lacks the typical feature of idiopathic case must be imaged like: 1. Young age groups 2. Abnormal finding in the trigeminal nerve examination like sensory defecate 3. long lasting episodes of pain and associated other cranial nerve palsied in the CPA like the 8th,7th and 10th cranial nerve 4. TN not responding to the usual medical treatment and associated with any abnormal neurological findings in the examination Conclusion: The trigeminal neuralgia mostly occur in old age so any young patient with sign and symptom of TN, CT or an MRI is indicated to excluded brain abnormality or any pressure on the 5th cranial n or its ganglia