title: [Amyloid pseudotumor disclosing non-secretory myeloma. Ultrastructural demonstration of the role of histiocytes in intratumoral amyloidogenesis].
abstract: A 69 year old woman presented initially with an amyloid tumour of the rib. Six months later, she developed a plasma cell tumour of the left acromion diagnosed as an IgG kappa myeloma. Electron microscopy of the initial costal lesion and the plasma cell tumour showed a close resemblance between the dystrophic plasmacytes, which had no morphological evidence of intracytoplasmic amyloid fibrils, and the histiocytes, many of which contained these fibrils and were probable sites of amyloid secretion. This suggests that the costal amyloid tumour was probably the result of transformation of a previous plasma cell tumour, and that intra-tumoural amyloid deposits have the same origin as the systemic amyloidosis observed in cases of multiple myeloma, i.e. the histiocyte.
mesh_terms: D000174:Acromion / Q000648:ultrastructure; D000368:Aged; D000686:Amyloidosis / Q000209:etiology*; D001859:Bone Neoplasms / Q000378:metabolism / Q000648:ultrastructure*; D003937:Diagnosis, Differential; D005260:Female; D006644:Histiocytes / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D007074:Immunoglobulin G; D007145:Immunoglobulin kappa-Chains; D008854:Microscopy, Electron; D009101:Multiple Myeloma / Q000175:diagnosis* / Q000648:ultrastructure; D012272:Ribs / Q000473:pathology
chemical_list: D007074:Immunoglobulin G; D007145:Immunoglobulin kappa-Chains
vernacular_title: Pseudo-tumeur amyloïde révélatrice d'un myélome non excrétant. Mise en évidence ultrastructurale du rôle des histiocytes dans l'amyloïdogenèse intratumorale.