Monoclonal gammopathies which do not meet the criteria of plasma cell myeloma, plasmocytoma or B-Cell lymphoma with plasmacytic differentiation. Monoclonal immunoglobulin serum levels are lower than 30 g/l, the marrow contains less than 10% of monocloal plasma cells with no signs of organ affection (no hypercalcemia, renal insufficiency, anemia or osteolytic lesions).