[Waldenstrom's macroglobulinemia with antibasement membrane activity of monoclonal immunoglobulin].

INTRODUCTION: Waldenström macroglobulinemia is a rare hematologic disorder with characteristic malignant plasma cell proliferation associated with the secretion of a IgM monoclonal immunoglobulin which is the cause of most of the clinical manifestations. Skin involvement is exceptional. We report a new case of Waldenström macroglobulinemia discovered in a patient who developed specific skin lesions with monoclonal immunoglobulin deposits. CASE REPORT: A 50-year-old woman developed spontaneously painful infiltrated erythematopapular plaques over the extension aspects of the limbs. There were no other clinical manifestations. The patient had a kappa IgM monoclonal gammapathy. The diagnosis of Waldenström macroglobulinemia was proposed after the discovery of voluminous intra-abdominal adenopathies and was confirmed by immunohistochemistry of the biopsies, indirect immunofluorescence evidenced reactivity against the epidermal basal membrane. Chemotherapy led to successful regression of the skin lesions, the tumoral mass and circulating IgM. DISCUSSION: This is the second reported case of Waldenström macroglobulinemia with anti-basal membrane monoclonal immunoglobulin. This IgM would recognize an 82 kD antigen on the dermal side of the dermo-epidermal junction situated in the anchoring fibres of the lamina densa, a zone classically involved in acquired bullous epidermolysis.