A case of diffuse plane xanthomatosis assoicated with systemic amyloidosis and multiple myeloma at its outset is reported. Plane xanthomatosis is certainly an autonomous entity in comparison with systemic amyloidosis, for there are no amyloid deposits in xanthoma. The patient had lambda type IgG paraproteinemia, with Bence-Jones proteinuria. Lipid tests were considered as normolipemic though some levels recall a type IV hyperlipoproteinaemia. A review of literature about the association "xanthomatosis-multiple myeloma" was made, after the important work of Bazex, Dupré and Mrs. Christol-Jalby. It allows us to distinguish two differnet descriptions: 1. When there is hyperlipoproteinemia, all clinical types of xanthomas may exist; multiple myeloma is generally typical (but sometimes not very progressive). 2. When there is normolipidemia, the main clinical type is diffuse plane xanthomatosis; multiple myeloma is atypical and often only a monoclonal gammapathy is found. 3. However in both cases, the outstanding clinical type is diffuse plane xanthomatosis: whether normo- or hyperlipemic, this therefore indicates a possible underlying disease, and above all a multiple myeloma.