Congenital fibrosis of type II extraocular muscles, diagnosis by MR imaging. A case report

Abstract

Congenital fibrosis of the extraocular muscles is a very rare ocular motility disorder that presents in the first months of life due to restricted vertical eye movement, palpebral ptosis, and chin elevation to correct the visual field. Muscular fibrosis occurs secondary to abnormal development involving part or all of the nucleus and oculomotor nerve and its innervated extraocular muscle;
the trochlear and external oculomotor nerves are less frequently affected. Complete knowledge of the cranial nerve course, MRI correlation, and clinical features of cranial nerve palsy is important for radiologists and neurologists to evaluate patients thoroughly. Cranial nerve imaging is usually performed using thin section T2-weighted images based on gradient echo imaging or turbo spin echo sequences, which show the cranial nerves as dark linear structures in contrast to the high signal intensity of the surrounding cerebrospinal fluid. In this article, we review the radiological findings of congenital fibrosis of the extraocular muscles based on brain anatomy and highresolution magnetic resonance imaging.