A case of chronic progressive external ophthalmoplegia

Abstract

A 56-year-old female with no ocular or visual complaints was found to have an oculomotor disturbance on routine health screening and was referred for ophthalmologic evaluation. A general physical examination, ophthalmic examination, and biceps brachii muscle biopsy were performed, leading to the diagnosis of chronic progressive external ophthalmoplegia (CPEO). Hematoxylin and eosin staining of the muscle biopsy specimen showed myogenic changes and modified Gomori-trichrome staining revealed the presence of 'ragged-red' fibers. Scattered cytochrome c oxydase-deficient fibers were also seen under light microscopy. Electron microscopy disclosed a subsarcolemmal accumulation of abnormal mitochondria. Southern blotting hybridization and polymerase chain reaction evaluation of the muscle biopsy specimen failed to detect deletion of mitochondrial DNA. Unlike Kearns-Sayre-Shy syndrome, the results of fundoscopic examination; fluorescein fundus angiography, electroretinography, and visual field testing in this patient were normal, and the results of electrocardiography were also normal.