Orbital solitary fibrous tumor: A painless mass after a dacryochystorhinostomy.

The solitary fibrous tumor (STF) is a rare spindle cell tumor that most often occurs in the pleura, mediastinum and other serosal sites, but it can be found anywhere. The authors present a case report of a 35-year-old male who was submitted to an eventless left external dacryocystorhinostomy (DCR) due to epiphora. During the surgery no tumors or anomalous tissues were visualized. Five months later the patient presented a painless mass at the lower medial quadrant of the left orbit, near the lacrimal fossa. A computed tomography, a magnetic resonance imaging and an orbital ultrasound were performed. A round, very vascularized and highly contrast enhanced mass was found. An anterior orbitotomy was done. Histological aspects and immunohistochemical markers were consistent with STF. The tumor was not visualized during the DCR. The authors think that the growth of the tumor and the weakening of the tissues in the medial canthus after the DCR allowed the tumor to move anteriorly within the orbit.