Multiple Orbital Dermoid Cysts Located within the Superior Oblique Muscle

We describe clinical and radiologic findings and surgical outcome of an orbital dermoid cyst located in the superior oblique muscle tendon. This unusual location for dermoid tumors has not been reported previously. Case report : A 15-year-old girl referred to us with an orbital mass in superonasal quadrant of the left orbit reportedly to be present from birth. Computed tomography revealed a cystic mass in the superonasal quadrant of the left orbit. Surgical excision through an incision at the medial of the upper lid crease showed two well-circumscribed masses surrounded by superior oblique muscle tendon. Results of histopathologic evaluation showed a dermoid cyst. Postoperatively, the patient did well with no change in her clinical finding. The findings in this patient demonstrate an unusual presentation for dermoid cysts; such pathologies could be included in the differential diagnosis of an enlarged extraocular muscle (EOM).