= BRONZED SCLEROSING ENCEPHALOMYELITIS

= inherited metabolic disorder characterized by progressive demyelination of cerebral white matter + adrenal insufficiency

Etiology: defective peroxisomal fatty acid oxidation ← impaired function of lignoceryl-coenzyme A ligase with accumulation of saturated very long chain fatty acids (cholesterol esters) in white matter + adrenal cortex + testes

Dx: assay of plasma, red cells, cultured skin fibroblasts for the presence of increased amounts of very long chain fatty acids

Mode of inheritance:

1. X-linked recessive in boys (common)
2. autosomal recessive in neonates (uncommon)

Histo: PAS cytoplasmic inclusions in brain, adrenals, other tissues

Age: 3–10 years (X-linked recessive)

• loss of hearing (50%), ataxia
• deteriorating vision (27%), optic disk pallor
• adrenal gland insufficiency → abnormal increased pigmentation, elevated ACTH level
• altered behavior, attention disorder, mental deterioration, death

Location: disease process usually starts in central occipital white matter → advances anteriorly through internal and external capsules + centrum semiovale → centripetal progression to involve subcortical white matter → interhemispheric spread via corpus callosum particularly splenium → involvement of optic radiation ± auditory system ± pyramidal tract

CT:

• large symmetric low-density lesions in occipitoparieto-temporal white matter (80%) advancing toward frontal lobes + cerebellum
• thin curvilinear / serrated enhancing rims near edges of lesion
• initial frontal lobe involvement (12%)
• calcifications within hypodense areas (7%)
• cerebral atrophy in late stage (progressive loss of cortical neurons)

MR:

• hypointensity on T1WI in affected areas (= hypointense atrophic splenium of corpus callosum)
• bilateral confluent hyperintense areas on T2WI

Prognosis: usually fatal within several years after onset of symptoms