A CASE OF UNILATERAL CONGENITALLY ENLARGED EXTRAOCULAR-MUSCLES

Background: Enlargement of extraocular muscles is an uncommon finding in children. Little has been written in the literature about possible causes. Methods: The authors present the clinical findings of a young girl who had unilateral congenitally enlarged extraocular muscles at 8 months of age. She underwent computed tomography (CT) and magnetic re sonance imaging (MRI) scans, systemic assessment, and extraocular musc le biopsy to determine a cause for the enlarged muscles. Results: The patient had a unilateral left esotropia and hypotropia at birth that w as nonprogressive. High-resolution CT and MRI scans showed enlargement of the left inferior rectus, lateral rectus, and medial rectus muscle s. Strabismus surgery undertaken at 2 years of age showed that the aff ected muscles were restricted on forced duction testing but were macro scopically normal in appearance. A biopsy specimen of the left lateral rectus muscle was processed for histologic, histochemical, and electr on microscopic studies, but no abnormal pathologic findings were found . Conclusion: This patient's constellation of findings appears to be u nique: it does not follow any previously reported pattern of disorders of extraocular muscle enlargement.