Pseudotumoral (para-articular) amyloidosis in non-myelomatous monoclonal gammopathy.

A case of non-myelomatous monoclonal gammopathy, with the unusual presenting features of recurrent "pseudotumoral" localized amyloid deposits in intimate relation with the shoulder joints, is described. The peculiar anatomo-clinical features, which make this case quite different from the most reported ones of amyloid arthropathy and of localized amyloidosis, are discussed. The pathogenetic implications are analyzed with special reference to the various known mechanisms, none of which seems to provide a completely satisfactory explanation of the genesis of this form.