[Specific cutaneous localizations in multiple myeloma and Waldenström's macroglobulinemia. Apropos of 4 cases].

The specific skin locations of multiple myeloma (M. M.) and Waldenström's macroglobulinemia (M. W.) are rare. The authors report here 4 cases: 2 within M. M., the other 2 within lymphoplasmocytic lymphomas with IgM dysglobulinemia (M. W.) or in situ tumoral secretion of IgM. Observation no. 1. A 56-year-old man is admitted for investigations for spontaneous fractures of the ribs. The skin examination reveals about ten purple, nodular and sometimes ulcerated lesions of the back which appeared over more than one year. The histology of a cutaneous nodule shows a dense infiltrate of plasma cells with numerous atypical cells. The laboratory investigations reveal a IgG, kappa M. M. A polychemotherapy leads to a healing of the nodules in 3 months. Observation no. 2. A 58-year-old man is admitted for investigations of a proteinuria (6.80/24 h) which will be imputed to a lambda chains M. M. One year and a half later appear subcutaneous thoracic nodules. The histology of the skin confirms the diagnosis of metastatic skin plasmocytoma; the patient will die a few months later in spite of the chemotherapy. Observation no. 3. A 84-year-old woman is admitted for investigations of a dysglobulinemia. On the cutaneous part there are tumoral purple plaques symmetrically disposed on the 2 cheeks and the nose. The histology of the skin shows a dermo-hypodermal tumoral infiltrate essentially made of lymphoplasmocytoid cells. In direct immunofluorescence study there is a kappa tumoral secretion of mu type.(ABSTRACT TRUNCATED AT 250 WORDS)