Background: The coexistence of plasma cell neoplasia such as multiple myeloma (MM) or monoclonal gammopathy of underdetermined significance (MGUS) with myeloid neoplasia such as myelodysplastic syndrome with excess blasts (MDS-EB) is exceedingly rare. Seeking to understand the clinical features of this dual hematological neoplasm and exploration of novel therapeutic approaches is warranted.
Methods: The cases of 7 patients diagnosed with both MGUS/MM coexisting with MDS-EB were reported. Moreover, this study reviewed and summarized 34 published cases of MDS including 7 cases of MDS-EB, describing the coexistence with plasma cell disease, and analyzed the clinical characteristics and survival of these cases.
Results: In total, 14 cases (7 reported here and 7 previously published) of MGUS/MM coexisting with MDS-EB were analyzed. Of these 14 patients, the median age was 65.5 years. Almost all (85.7%) participants had severe anemia or pancytopenia, and nearly half (42.9%) of the cases developed into acute myeloid leukemia (AML). Half of the participants showed osteolytic lesions. The median bone marrow plasma cell count was 23.0%, and the median myeloid blast count was 7.5%. Immunological analysis using flow cytometry confirmed the coexistence of 2 different clones, malignant myeloid clone (CD34+, CD117+, HLA-DR+, CD33+, and CD13+) and plasma clone (CD38+, CD138+, and CD56+). Patients with MGUS/MM and MDS-EB experience very poor therapeutic responses. A great number of patients (64%) were reported to have no response or rapid relapse. The median overall survival (OS) was only 8 months for patients with MGUS/MM and MDS-EB, which was significantly shorter than that of those with MGUS/MM and MDS-other type (median OS of 52 months) (P=0.0009).
Conclusions: Herein, a type of malignant myeloid clone concurrent with plasma clone was reported, without previous exposure to chemotherapy, and poor prognosis of these patients was observed. However, standard treatment methods are still absent, which therefore heightens our awareness of this type of disease and the urgent need for further investigation to prolong survival.
Keywords: Myelodysplastic syndrome with excess of blasts (MDS-EB); coexistence; monoclonal gammopathy of underdetermined significance (MGUS); multiple myeloma (MM); prognosis.