Can a dermoid cyst lead to an abnormal origin of an extraocular muscle?

ABSTRACT

A 5-year-old boy presented with a large 5 cm × 5 cm cyst covering the left eye completely since birth. The cyst was excised in toto and was sent for histopathological examination. During the surgery, the inferior oblique (IO) muscle was seen originating from medial orbital wall, 10-12 mm behind the medial orbital margin, just posterior to the lacrimal bone and moving laterally, downward, and posteriorly from its origin making a more acute angle - around 20° to its site of origin. The insertion of the IO to sclera was at its normal site. The abnormal origin of IO was confirmed later by magnetic resonance imaging. The ocular movements of the left eye were tested 2 weeks after the surgery and were found to be normal in all directions. However, the child was hypertrophic and amblyopic. The histopathological findings showed the orbital cyst to contain dermal elements, respiratory, and intestinal epithelium.