Amyloidosis and Light Chain Plasmocytoma

Abstract

Nine cases of light chain plasmocytomas, 6 type λ and 3 type k, have been studied in reference to amyloid presence and localisation. Bone marrow plasmocytosis, light chains in serum and/or in the urine, and osteolytic lesions were demonstrated in all the patients. Initial symptoms, i.e., macroglossia and lymphadenopathy, were secondary to amyloid deposits in two patients; the absence of overt evidence of plasmocytoma had previously led to the diagnosis of « primary » amyloidosis in one case. Amyloidosis may therefore be associated with concealed plasmocytomas, evident only after a certain period of time. Amyloidosis was not detected in the sites where it was clinically suspected in two cases. However, on bone marrow aspirates, amyloid was present in seven patients where thioflavine T appeared as homogeneous, amorphous, intercellular substance localised in small areas.