Tumour-like localized amyloid of the brain is derived from immunoglobulin light chain.
A patient is presented in whom the amyloid component of an intracerebral 'amyloidoma' has been purified and characterized by amino acid sequence analysis. The material originated from an autopsy of a 76-year-old man who 15 years earlier had been operated for an intracerebral 'amyloid tumour'. The tumour had recurred and grown to an almost walnut-sized mass in the right cerebral hemisphere. It was located in the parietal lobe close to the lateral ventricle and had a close connection to the choroid plexus. Histological examination showed large masses of amyloid surrounded by some plasma cells and a few macrophages of the foreign body type. Amino acid sequence analysis of a major fibril subunit protein showed homology with the variable region of a monoclonal lambda immunoglobulin light chain, subgroup III or IV. This shows that the amyloid in the 'tumour' was of AL type and presumably derived from local synthesis by plasma cells.
Eriksson
L
L
Department of Pathology, University of Uppsala, Sweden.
Sletten
K
K
Benson
L
L
Westermark
P
P
D000368:Aged; D000595:Amino Acid Sequence; D000682:Amyloid / Q000737:chemistry / Q000302:isolation & purification; D000686:Amyloidosis / Q000276:immunology*; D001927:Brain Diseases / Q000276:immunology*; D002850:Chromatography, Gel; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000032:analysis*; D007150:Immunohistochemistry; D008297:Male; D008853:Microscopy; D008969:Molecular Sequence Data
D000682:Amyloid; D007147:Immunoglobulin Light Chains