Amyloidosis of specialized mesodermal tissues in non-myelomatous monoclonal gammopathy. A pathogenetic hypothesis.

The follow-up and the pathological findings of a previously described case of non-myelomatous monoclonal gammopathy with relapsing localized amyloid masses of the shoulder joints are reported. The peculiar "mesodermal" distribution of amyloid deposits, strictly limited to tissues lined by mesothelial or endothelial cells emphasizes the role of local factors in the pathogenesis of amyloidosis thus supporting the hypothesis that amyloid deposition can be related also to some differentiated tissues with peculiar local susceptibility. The morphological findings of the present case enable the Authors to suggest a pathogenic mechanism for amyloid deposition.