Anomalous extraocular muscles with strabismus

Abstract

An 8-month-old boy with Gorlin syndrome presented with a large right-face turn and constant exotropia of the left eye. Eight-millimeter recession of the left lateral rectus muscle was performed at 23 months of age without complete postoperative improvement. Orbital imaging revealed bilateral anomalous extraocular muscles inferolateral to the optic nerves. Surgical resection of the tissue confirmed the accessory musculature with postoperative correction of the strabismus. To our knowledge, this appears to be the first reported case in the radiologic literature.

Fig 1.

Coronal unenhanced CT scan of the orbits at the level of the ethmoid sinuses demonstrates bilateral accessory extraocular muscles (arrows) medial to the lateral rectus muscles, superior to the inferior rectus muscles, and inferolateral to the optic nerves. Attenuation is similar to that of surrounding extraocular muscles. The structure is much larger on the left side.

Fig 2.

Axial unenhanced CT scan of the orbits at the level of the greater sphenoid wing demonstrates accessory extraocular muscles (arrows) medial to the lateral rectus muscles and lateral to the optic nerves (not shown on this image) that arise from the orbital apex at the annulus of Zinn and insert directly on the posterior globe, with no bridging connection or assimilation into the surrounding muscles.