On the dual nature and lack of specificity of intracytoplasmic inclusions in a case of adult onset orthochromatic leukodystrophy

Adult-onset leukodystrophy: review of 3 clinicopathologic phenotypes and a proposed classification

Adult-onset leukodystrophies are clinically and pathologically heterogeneous diseases, and the overlapping morphologic features among these disorders can lead to confusion in pathologic classification. We report 3 recent autopsy cases that illustrate the clinicopathologic distinction between the 3 entities. The first, autosomal dominant leukodystrophy, is characterized clinically by early autonomic dysfunction and genetically by LMNB1 (lamin B1 gene) duplication. Recently, another clinical subtype emerged without the early autonomic dysfunction but with a similar genetic abnormality documented in 1 family. We reviewed the reported autopsy cases and show that both clinical subtypes share distinctive pathologic features. Other forms of adult-onset leukodystrophy can be classified based on the histologic evidence of the primary pathologic processes. A case of axonopathy with secondary demyelination serves as a prototype for adult-onset leukoencephalopathy/leukodystrophy with axonal spheroids; the genetic mutation of CSF1R (colony stimulating factor 1R) was recently discovered in patients with this disorder. A case of a primary demyelinating disease with no other distinctive pathologic features is designated as orthochromatic leukodystrophy. Pigmented glia can be present in both of the latter two categories and should not be used as a differentiating diagnostic feature. Based on the observations of our cases and literature review, we propose an algorithm for a practical diagnostic approach to adult-onset leukodystrophies.

Autosomal dominant leukodystrophy with axonal spheroids and pigmented glia: clinical and neuropathological characteristics

We report two autopsy cases of siblings with adult-onset autosomal dominant leukodystrophy characterized by destruction of cerebral white matter, large numbers of axonal spheroids and pigmented glia in the fronto-temporal lobes. Both patients presented with motor and cognitive symptoms and aphasia, 2-3 years before death. At autopsy, the brain showed brown coloration and decreased volume of white matter in the frontal and temporal lobes as well as corpus callosum. Microscopically, marked loss of myelin and axons and abundant axonal spheroids without apparent neuronal loss were observed in the frontal and temporal lobes, which was consistent with hereditary diffuse leukodystrophy with spheroids (HDLS). In addition, glial cells, most consistent with macrophages and containing pigments that were stained by Sudan III and PAS, were found in the white matter lesions. The present cases showed overlapping features with HDLS and pigmentary type of orthochromatic leukodystrophy, suggesting that the pathomechanisms of these two diseases are closely related.

Adult onset pigmentary orthochromatic leukodystrophy with ovarian dysgenesis

Pigmentary type of orthochromatic leukodystrophy (POLD) is an adult-onset leukodystrophy, characterized pathologically by the presence of glial and microglial cytoplasmic pigment inclusions. The complete phenotype, genotype and pathogenetic mechanisms in POLD have not been elucidated. We followed for 18 years a woman with autopsy-proven POLD, who presented with 'frontal' dementia and spasticity. Her further course was marked by progressive mutism, apraxia and seizures. Her sister had died of the same disease after a much more rapidly progressing course. These sisters had primary infertility with pathologic evidence of streak ovaries. Diagnosis was confirmed in both cases by post-mortem examination. POLD is a rare cause of adult-onset leukodystrophy presenting with dementia. Ovarian dysgenesis is extremely rare in the absence of demonstrable chromosomal abnormalities and extends the clinical spectrum of POLD.

A rare form of adult onset leukodystrophy: orthochromatic leukodystrophy with pigmented glia

BACKGROUND

Orthochromatic leukodystrophy with pigmented glia and scavenger cells is a rare leukodystrophy of unknown etiology. This report describes a 42-year-old man with a history of depression, dementia and parkinsonism having the pathological features of orthochromatic leukodystrophy with pigmented glia.

METHODS

We reviewed the clinical history and pathology of autopsy and brain biopsy material.

RESULTS

Imaging revealed bilateral cerebral white matter hypodensities. At autopsy, the brain demonstrated a leukodystrophy affecting predominantly the cerebral hemispheres and characterized by demyelination, and cytoplasmic pigment deposits in oligodendroglia and astrocytes. The pigment had the staining properties of ceroid-lipofuschin and on ultrastructural examination was composed of membrane-bound lipid and electron-dense inclusions which had a fingerprint-like pattern. Similar pigment inclusions were not observed on ultrastructural examination of renal, splenic or hepatic tissue obtained at autopsy. The brain biopsy contained cerebral cortex with sparse subcortical white matter in which a few oligodendroglia and fewer astrocytes at the grey/white junctions showed cytoplasmic pigmentary inclusions identical to those described above. However, due to the paucity of white matter in the specimen a definite diagnosis of orthochromatic leukodystrophy with pigmented glia was not made.

CONCLUSIONS

The diagnosis of orthochromatic leukodystrophy with pigmented glia and scavenger cells can only be made antemortem if the brain biopsy contains adequate white matter and although a rare condition, it should be considered in the differential diagnosis of an adult onset leukodystrophy.

A case of pigmentary type of orthochromatic leukodystrophy with early onset and globoid cells

We report herein a sporadic case of the pigmentary type of orthochromatic leukodystrophy with early onset and very rapid clinical course. The patient's development was normal until 2 years old, when he experienced visual disturbance. Rapid deterioration resulted in death 1.5 years after the onset. Metachromatic leukodystrophy, globoid cell leukodystrophy and adrenoleukodystrophy were excluded by biochemical assays. Autopsy findings were compatible with the diagnosis of the pigmentary type of orthochromatic leukodystrophy. However, there were unique findings of severe neuronal loss and the collection of globoid-like cells in the interface of the gray matter and the white matter. Immunohistochemical staining of myelin basic protein, proteolipid protein and galactocerebroside demonstrated that these myelin constituents were equally preserved in the posterior column, while absent in the lateral and anterior columns of the spinal cord.