title: Monoclonal gammopathy--a diagnostic challenge. Illustrated by four cases of multiple myeloma with an unusually indolent (smoldering) course.
abstract: Four patients with IgG multiple myeloma (MM) and an unusually indolent course are presented. They had received no cytostatic therapy for 12--23 years. The M-component was initially 25--33 g/l, the bone marrow plasma cell percentage was 4--6%, but bone lesions were not demonstrated. A marked increase in size of the M-component and in the plasma cell percentage was noted in all patients, but a definitely neoplastic proliferation in only one patient. Spontaneous regression of the M-component was observed in two patients. In the light of the present cases we believe that neither a high level of the M-component nor an increase in its size should be used alone as indicators of a malignant course in MM patients. An indolent, non-progressive variant obviously occurs as one extreme in the clinical spectrum of this disorder with a course sometimes extended over 10--20 years.
mesh_terms: D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000175:diagnosis*
chemical_list: D007074:Immunoglobulin G