AL-KAPPA AMYLOID IN A SOLITARY EXTRADURAL LYMPHOMA

A 68 year old man with a 10 year history of apparently benign IgM kapp a paraproteinaemia presented with dysarthria, left hemiparesis, and a sensory peripheral neuropathy. A calcified right temporoparietal extra dural mass was shown by scintigraphy with I-123-serum amyloid P compon ent to contain amyloid. There were no extracranial amyloid deposits. C linical improvement followed craniotomy and partial resection of tissu e which consisted of amyloid and a mixed mononuclear cell infiltrate. The amyloid fibrils consisted of the framework 1 region of the variabl e domain of monoclonal kappa(IV) immunoglobulin light chains. There wa s a prominent B-cell clonal immunoglobulin gene rearrangement in the t umour tissue, supporting a diagnosis of lymphoplasmacytic lymphoma, bu t no sign of systemic lymphoma. Neurological state, tumour volume, and quantity of amyloid have remained static for two years after treatmen t with chlorambucil.