[Pyoderma gangrenosum and biclonal gammapathy probably due to multiple myeloma (author's transl)].

The authors report the observation of pyoderma gangrenosum (P. G.) leading to the discovery of an underlying biclonal gammapathy, which despite the absence of bony lesions, almost certainly represents a malignant myeloma. The authors have reviewed the different known associations with pyoderma gangrenosum, with special reference to benign and malignant gammapathies. Rare cases of biclonal gammapathies with pyoderma gangrenosum have been published but none of a malignant nature. This therefore appears to be the first reported cases. The authors are aware of the reported tendency of pyoderma gangrenosum lesions to appear in areas of previous trauma, as may be the case in this patient. Finally systemic corticosteroid therapy produced a rapid remission of the skin lesions, but with the reactivation of known treated pulmonary tuberculosis.