Histiocytoma is a tumor with mesenchymal etiology, whose primary orbital form is very rare. (1) Although it is a benign tumor, there have been written--in a few cases--it's metastatic forms too. This article describes the case of a female patient with this tumor which had been extirpated successfully and without any recurrences till now. The disease had been appeared with a chronic sphenoidal and maxillary sinusitis. At the same time there are described the latest concepts about these tumors' etiology, classification and their treatment.