Congenitally enlarged extraocular muscles: Can congenital thyroid eye disease exist in a euthyroid infant?

A 2-month-old boy presented with hypotropia, eyelid retraction, and proptosis of the left eye. CT and ultrasound demonstrated enlarged extraocular muscles. Both the infant and mother were euthyroid. The patient underwent inferior rectus; recession, lower eyelid retractor disinsertion, and entropion repair. Biopsy of the inferior rectus and oblique muscles was normal. The clinical presentation and workup appear to be most consistent with thyroid eye disease, which, to our knowledge, would be the first reported case of euthyroid congenital thyroid eye disease with a euthyroid mother.