[Multiple myeloma after monoclonal gammopathy of uncertain significance. Study of 10 patients].

PURPOSE: To analyse the clinical, biological and evolutive characteristics of 10 patients with multiple myeloma (MM) previously diagnosed of monoclonal gammopathy of uncertain significance (MGUS).

PATIENTS AND

METHODS

Ten patients with diagnostic criteria of MM, included in a series of 114 subjects with MGUS, IgG (92 cases), IgA (21 cases) or biclonal IgG+IgA (1 case), diagnosed between 1970 and 1990, comprise this study group.

RESULTS

The actuarial risk of developing MM in the series of 114 MGUS was 7.25% (95% CI: 1.5-13) and 16.1% (05% CI: 4.7-27.5) at 5 and 10 years of follow-up, respectively. MM occurred suddenly, both on clinical and biological grounds, in 8 of the 10 patients. The median period between the diagnosis of MGUS and the onset of MM was 48 months (range, 12-153). IgG MM appeared in 5 instances and IgA MM in 5 others. Bone pain (7 cases) and hypercalcaemic encephalopathy (2 cases) were the commonest clinical manifestations. Osteolytic lesions were found in the x-ray scan in 9 patients. Eight patients received chemotherapy, objective response being seen in five of them. The median survival since the diagnosis of MM was 18 months (range, 0.1-95). The causes of death in 8 deceased patients include disease progression (4 cases), pneumonia (3 cases) and neoplasm of the bladder (1 case).

CONCLUSIONS

This analysis shows the difficulties in predicting the outcome of MGUS, since most of the MM seen here occurred abruptly and after a highly variable length of time. Thus, patients with MGUS must be followed-up for undetermined time.