Facial Diffuse Plexiform Neurofibroma-associated Mandibular Deformities: Surgical Interventions and Monitoring of Treatment Results in a Patient for Over 40 Years.

Background/aim: Neurofibromatosis type 1 (NF1) is an autosomal dominant hereditary tumor-predisposition syndrome and a genetic bone disease. The case report describes tumor-associated mandibular changes, their therapy and follow-up over several decades. The aim of the presentation is to highlight the tumorous and hamartomatous components of the facial skeleton and to examine the stability of surgical measures over the long term.

Case report: A 13-year-old male patient had developed an extensive diffuse plexiform neurofibroma of the left cheek and neck region. Radiological examination showed a mandibular defect, which enlarged over time. Surgical treatment consisted of a corrective procedure for the asymmetrical bony chin and augmentation osteoplasty of mandibular defect. The transplant was an integral part of a functionally stable bone for decades.

Conclusion: Head and neck diffuse plexiform neurofibroma can be associated with craniofacial bone malformations. Distinction between deformity-related bone changes from an infiltrating and destructive tumor can be difficult, especially in cases of rapidly progressive local bone loss. Presumably, both tumor-associated functional lesions of the masticatory muscles and tumor-related effects on the bone influence the shape of the affected bone. Diagnosis of tumor-associated bone lesions can be challenging in NF1. Reconstructive bone surgery of the jaw provides options for functional and esthetic improvement of the affected individual. However, long-term follow-up checks are advisable to assess treatment results. An exact assessment of the tumor type and long-term monitoring of the findings are the basis of a viable surgical therapy.