Bone absorption and deformity in mandible as initial symptom and manifestation of neurofibromatosis type 1: A case report and literature review

Neurofibromatosis type 1 (NF-1) is an autosomal dominant inherited genodermatosis disease and tumor susceptibility syndrome with a prevalence of 1/6000–1/3000 reported in most epidemiological studies and 1/3333–1/2558 in live births. NF1 is caused by pathogenic variants in the NF1 gene on autosome 17q11.2, and characterized by abnormal pigmentation of the skin，such as café-au-lait macules (CALM), freckles in the armpits or groin area. Additionally, NF1 patients frequently have optic path-way gliomas (OPG), Lisch nodules, plexiform neurofibromas, skeletal abnormalities (dysplasia of long bones, scoliosis), learning and behavioral disabilities, autism spectrum symptoms, seizures, sleep disorders, vasculopathies (moyamoya syndrome, renal artery stenosis) and non-neurological cancers (breast cancer, pheochromocytoma). Among tumors involving the nervous system, peripheral nerve sheath tumors (cutaneous and plexiform neurofibromas) predominate, and 8–13 % of plexiform neurofibroma patients developing malignant peripheral nerve sheath tumors. We report a case of NF1 with initial symptom and manifestation in low jaw in this paper and review the relevant literature to introduce the epidemiological characteristics, pathogenesis, clinical manifestations, latest diagnostic basis and follow-up of NF1.