Teratoma: In rare cases, misdirected or ectopic germ cells in the orbit can give rise to a teratoma. These tumors can result in massive proptosis. All three germ cell layers are represented in the lesion which results in compression and destruction of normal orbital tissue without frank infiltration. Teratomas are usually treated by exenteration although local excision has been successfully performed in select cases. CT scans may show calcification and occasionally structures that resemble teeth. Back to Orbit