Background: Fibrous histiocytomas are a diverse group of soft tissue tumors classified histiologically as benign, locally aggressive, and malignant. These tumors are found throughout the body, but seem to have an affinity for the periorbital area. They account for one percent of all ocular masses and are the most common primary mesenchymal tumor of the orbit. Associated ocular signs and symptoms include decreased visual acuity, proptosis, diplopia, pain, restricted extraocular muscle movement, swelling of the eyelids, and conjunctiva, as well as disk edema.
Case report: A case of a benign orbital fibrous histiocytoma is presented. The patient reported intermittent pain and occasional diplopia; severe edema of the right upper eyelid; and proptosis and inferior vertical displacement of the right globe were observed. Computed tomography revealed a well-defined mass that was subsequently surgically removed and histopathological results from the Armed-Forces Pathology Institute confirmed the diagnosis.
Conclusions: Orbital fibrous histiocytomas are rare periocular tumors that can manifest multiple ocular signs and symptoms. Careful histologic examination is necessary for diagnosis, since these tumors have a wide range of morphology. Differential diagnoses include orbital masses with similar radiologic or histologic findings.