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Hematoxylin & eosin

Hematoxylin & eosin

History: This slide was taken from the archive and the history was not provided. This specimen was obtained from the autopsy of a case with know x-linked adrenoleukodystrophy.

Histologic Highlights of this Case:

• On casual examination, there does not seem to be much obvious pathologic changes. On careful examination, however, there are some foamy histiocytes in the white matter (Area 1 and 2). In the superficial part of the folia, the number of histiocytes are not that numerous (Area 1) but at the base of the cerebellar folia, however, there are many histiotyces (Area 2) and it seems like that the histiocytes are slightly expanding the white matter (Area 2).

• The presence of these foamy histiocytes indicates possible storage of abnormal substance and in this case adrenal lipids.

Comment:

• X-linked adrenoleukodystrophy is a leukodystrophy. Leukodystrophies are metabolic disorders that typically affect the white matter of the central nervous system. Although x-linked adrenoleukodystrophy is classically associated with demyelination, hematoxylin-eosin stain is not an appropriate stain for the presence (or absence) of myelin. (see bonus images)

• The ultimate diagnosis of metabolic diseases is based on biochemical studies. Pathologic studies can help to rule in and rule out some entities but is not the appropriate mean for establising a diagnosis.

• X-linked adrenoleukodystrophy is a peroxisomal disease with combined involvement of the CNS and the adrenal glands. Progressive childhood onset is the most common presentation but clinical presentation is quite variable. Pathologically, X-ALD is characterized by lipid accumulation (birefrigent striations, also seen in other peroxisomal diseases) in the adrenal gland and testicular interstitial glands and inflammatory "three-zone" demyelinating lesions in the brain.

• The etiology is due to mutation of the ALD gene located on chromsome Xq28. The ability to form coenzyme A derivatives of very long chain fatty acids (chain length over 22 carbon) is reduced. This lead to wide spread accumulation of very long chain fatty acid.

• ALD gene expression is highest in adrenal glands, intermediate in brain, and almost undectable in liver. ALDP is highly expressed in microglia, astrocytes, and endothelial cells; oligodendrocytes have little to none. This distribution lead to the clinical pattern of prominent accumulation of lipids in adrenal gland and the central nervous system.

Gross Photo

Luxol Bast Blue-Cresyl Violet

Hematoxylin-Eosin

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