Neurofibromatosis is a genetically inherital neurocutanous heterogenous disorders which affects skin, nerveous sytem or both and is a rare disorder in our country. NF type1 which appears per 2500-3000 births, is a defect in the 17q11.2 gene which is responsible for disorders. Cardinal symptoms; neurofibromas, cafe au lait spots, axillar-inguinal freckle and iris hamartoms (lisch nodules). In our case of a 22-years-old women, we detected neurofibromas, cafe au lait spots, lisch nodules and malign periferal nerve sheath tumor (MPNST) in left sacroiliac region by evaluating the patient for radicular pain. Under the view of these symptoms a rare coexistence of NF1 and MPNST is reported. As a result, radicular pain in patients presenting with symptoms of neurofibromatosis should be considered as the high possibility of underlying malignancy and the necessary imaging methods need to be planned.