We describe a 53 year old man with a two months history of frontal headache and right visual loss, with complete right blindness at the moment of diagnosis. Neither nasal obstruction nor endocrine symptoms were found. Computerized Tomography showed a neoplasm involving both paranasal sinuses and sellar region, with bilateral orbital extension. The patient underwent a bifrontal craniotomy with apparent complete excision. Histopathologic examination proved smooth muscle cells sarcoma (leiomyosarcoma). Clinical evolution was unfavorable, with rapid local recurrence. The patient died of cerebellar metastasis 4 months after the initial diagnosis and treatment. Leiomyosarcoma of the sinonasal tract is an unusual tumor, and we have found only 63 cases previously reported. The most frequent clinical presentation is nasal obstruction. Surgery is the treatment of choice, as far as radiotherapy or chemotherapy do not appear to slow disease progression. No relationship has been found between the aggressiveness of leiomyosarcoma of the sinonasal tract and morphologic parameters; instead, prognosis is dependent on the distribution of disease at clinical onset. Leiomyosarcoma of the sinonasal tract may be regarded as a locally aggressive neoplasm with only limited metastatic potential.