CONGENITAL ORBITAL CYSTS ASSOCIATED WITH THE COMMON SHEATH OF SUPERIOR RECTUS AND LEVATOR PALPEBRAE SUPERIORIS MUSCLES

Purpose: To review the clinical and operative features of a subgroup of superior congenital orbital cysts that intimately are associated with the common sheath of the superior rectus and levator palpebrae superioris muscles. Methods: Records from four eligible patients were reviewed retrospectively. Results: All four patients had ptosis or lid swelling at initial presentation and were found at surgery to have large cysts within the common tendon sheath of the superior rectus and levator palpebrae superioris muscles. The lining of these cysts resembled that of conjunctiva. There was no precedent conjunctival disease or surgery. Conclusions: The authors propose that these cysts are congenital and arise as misdirected cleavage of mesoderm during formation of the superior fornix. As such, this type of cyst has not been described previously and may represent a third group of congenital orbital cysts distinct from both conjunctival inclusion and dermoid cysts; Particular caution is required in their excision.