von Recklinghausen 病に合併した下顎歯肉癌の1例

抄録

Neurofibromatosis （NF） type 1, known as von Recklinghausen’s disease, is an autosomal dominant inherited disorder caused by a mutation of a gene on the long arm of chromosome 17. Malignant tumors are often observed in patients with NF, whereas oral carcinoma concurrent with NF is very rare. This paper describes a case of squamous cell carcinoma of the lower gingiva adjacent to a neurofibroma in a patient with NF type 1.
A 57-year-old man with NF type 1 was referred to our hospital. Intraoral examination revealed two masses: one was a firm nodule on the buccal shelf of the lower left posterior region covered by ulcerated mucosa, and the other was a soft to firm nodule adjacent to the other one in the left cheek region and was covered by normal mucosa.
Excisional biopsy of the two nodules was done. Histological examination showed that the nodule in the buccal region was squamous cell carcinoma （T2N0M0）, and the other was a usual type of neurofibroma. The patient underwent chemotherapy and radiotherapy, followed by local resection of the carcinoma. Local recurrence developed 1 month later. Mandibular segmental resection including the region of neurofibroma, followed by neck dissection and reconstruction with a rectus abdominus free flap was done. The patient has not had tumor recurrnce or metastasis for 8 years after mandibular resection.