Recurrent Diffuse Neurofibroma of the Mandibular Anterior Lingual Alveolar Process Associated With Dental and Skeletal Changes in Neurofibromatosis Type 1.

Neurofibromatosis type 1 (NF1) is a tumor predisposition syndrome and a bone disease. Dystrophic facial skull often is topographically related to diffuse neurofibromas (DNFs). The report traces the diagnosis and treatment of an oral DNF that was registered in adolescence and describes associated bone findings. The aim of the investigation was to illustrate and specify the interplay of tumor-associated and dysmorphic changes of the facial skull in NF1. This 14-year-old patient with NF1 had developed a solid tumor arising from the mandibular anterior lingual alveolar process. Histological examination of the tumor identified a DNF. Imaging showed a funnel-shaped vertical defect of the alveolar process between incisors, asymmetry of bony chin and vertical position of mental foramina. The chin showed irregular, bi-cortical connected bone canals suspected to indicate enlarged neurovascular channels. Thirteen years later, the patient developed a local tumor recurrence (DNF). Meanwhile, the anterior bone defect had become larger. However, the bony chin appeared considerably sclerosed. In contrast, mandibular shape and surface were unchanged. DNF can affect the position of teeth, invade the bone, and cause enlarged bone channels. Surface erosion and trophic effects of the mandible may arise adjacent to the neurogenic lesion. DNF of the oral cavity can recur. It is becoming apparent that the tumor-associated skeletal and dental changes in the mandible correlate with the time of development of the peripheral nerve sheath tumor. The findings could be useful as indications for an expanded tumor search in the affected area.