Fibrous Histiocytoma of Anterior Ethmoidal Sinus: Case Report and Review of the Literature.

Benign fibrous histiocytoma of the para nasal sinus is a rare tumor of this region which originates from mesenchymal cells. A 9-year-old girl presented with gradually enlarging mass above the medial canthus over 3 months. Orbital computerized tomography scan showed a round well-differentiated homogeneous mass in the anterior ethmoidal sinus. Histology and immunohistochemistry analysis after excision revealed proliferation of spindle-shaped fibroblasts in storiform pattern and histiocytes without mitosis and anaplasia. After 9 months from surgical excision, recurrence occurred which resulted in total excision again. This is the first reported case of benign fibrous histiocytoma involving the ethmoid sinus in Iranian people. Rare sinus tumor should be considered in the differential diagnosis of sinus tumors.