A rare case of giant multicystic solitary fibrous tumor of the orbit.

Solitary fibrous tumor (SFT) is a rare spindle cell tumor of the orbit of mesenchymal origin. Though these tumors are mostly solid, partial or complete cystic changes can rarely occur. Only six such previous cases of cystic fibrous tumor of the orbit have been mentioned in the literature. We report a case of an elderly male who presented with a huge left sided medial orbital mass. Magnetic resonance imaging showed a predominant cystic orbital mass separated by septae and suggested a diagnosis of Hydatid cyst. The patient underwent complete excision of the mass and histopathology and immunohistochemistry were suggestive of cystic SFT. Cystic degeneration in SFT is extremely rare and can be a harbinger of malignancy, and pose risk of recurrence. Close follow up and monitoring is required for all such cases.