Multiple Solitary Plasmacytoma:  Characteristics, Response To Therapy, Survival In Nine Patients From a Single Institute

  The International Myeloma Working Group in 2003 recognized a separate classification of plasmacytomas that occur as multiple sites of disease in soft tissue, bone, or both  as multiple solitaryplasmacytoma (MSP). There are only few cases of MSP described in literatures. As a rare mylema, relatively little is known about its features, treatment response, and survival.

  we have retrospectively analyzed nine patients with MSP in our hospital from 2009 to 2013.

The median age was 49 (26-49) years old. There were six males and three females. All but one had M-protein in serum and/ or urine. There was a predominance of lambda light chain (6/8). Most cases had multiple bone lesions (8/9).Only one had multiple solitary extramedullary plasmacytoma localized on CNS tissue and right lumber. Most (6/9) were stage III of DS for and seven cases were stage I of ISS. Six patients were treated with regimen containing bortezomib as induction therapy. And one of them underwent high-dose of chemotherapy with autologous stem cell transplantation (HDT/ASCT) at CR as part of their front-line therapy. Another three patients were treated with conventional alkylating agent combined with glucocorticoid based chemotherapy. After initial chemotherapy, seven patients reached CR, one PR. In first line combinational chemotherapy that containing bortezomib (Btz) (n=6), 100% patients achieved CR ,compared with that of 33.3% in patients treated with conventional chemotherapy (P =0.083). Date cut-off was July 20, 2013, a median follow-up of 28.5 (range2-38) months. The median OS time was 29, median progression -free survival (PFS) was 8 months. However, none of them progressed to MM. In addition, compared with the patients whose regimes included Btz (n=6), the patients who got conventional chemotherapy (n=3) had a trend towards poorer median OS (not reach versus 28 months, P = 0.116) and shorter median PFS (6 months versus 38 months, P = 0.356).

 MSP was at early stage at diagnosed. Most cases were male and λ light chain type. Although there was a good treatment response, these patients easily progressed. ISS may not suitable for evaluation of prognosis with MSP.Bortezomib based therapy could further deepen degree of remission , prolong the survival.

No relevant conflicts of interest to declare.