Vol.102 No.11 contentsPRACTICA OTO-RHINO-LARYNGOLOGICA
Vol. 102 No. 11 November 2009
A Case of Leiomyosarcoma of the Nasal Cavity with Neurofibromatosis Type 1
Yoshihiro Onoe, Shuji Koike, Takashi Nasu, Daisuke Noda,
Akihiro Ishida, Kenichi Ishii and Masaru Aoyagi
(Yamagata University School of Medicine)
We report a case of leiomyosarcoma of the nasal cavity with neurofibromatosis type 1 (NF1). Leiomyosacoma accounts for 5-7％ of all soft-tissue sarcomas and occurs most often in the gastrointestinal tract and uterus. Leiomyosarcoma of the sinonasal tract is rare.
A 66-year-old man with NF1 and reporting left nasal obstruction and recurrent epistaxis was found in endoscopic observation to have a reddish tumor of the left nasal cavity. Computed tomography (CT) of the paranasal sinuses showed an oval tumor arising from the inferior turbinate and filling the left nasal cavity. T1-weighted magnetic resonance imaging (MRI) showed the homogenous enhanced tumor to have almost the same signal intensity as a subcutaneous neurofibroma of the scalp. The nasal tumor was surgically removed by Deker's method. Immunohistochemical staining of the resected tumor showed tumor cells positive for a-smooth muscle actin and neuron-specific enolase, but negative for S-100 protein, CD34, and CD56. The tumor was diagnosed as a leiomyosarcoma. The patient was discharged without postsurgical treatment and is being followed up, showing no recurrence or metastasis as of this writing.
NF1 is an autosomal-dominant hereditary disorder that occurs in every 3,000 live births in Japan. The risk of malignancy among NF1 patients is higher than among the general population, i.e., the NF1 gene is a tumor suppressor gene of which mutation involves a fourfold increased risk for cancer. The NF1 gene product neurofibromin is thought to deliver much of its function by downregulating the oncogene ras. Leiomyosarcoma pathogenesis in our subject may thus be associated with the NF1 gene.
Our case is, to the best of our knowledge, the first clinical report of leiomyosarcoma in the head and neck region with NF1.
Key words :leiomyosarcoma, neurofibromatosis type 1, sinonasal tumor