Both chronic lymphocytic leukemia (CLL) and multiple myeloma (MM) are common hematological malignancies originating from mature B cells of different differentiation stage. However, it is quite rare that MM could develop after CLL diagnosed. We reported a 66-year-old female progressed forward myeloma 3 years after she was diagnosed as CLL and conducted an analysis to investigate the epidemiology and clinical features among these patients based on the Surveillance, Epidemiology, and End Results (SEER) database. Our data demonstrated that CLL patients were 19% less likely to develop myeloma than general U.S. population (standardized incidence ratio 0.81; 95% confidence interval 0.62-1.03), although without statistical difference. The median overall survival from CLL diagnosed was 90 (58.1-121.9) months, which was the same as general CLL patients according to historical data. But the outcomes of secondary MM was much poorer than general MM patients. Age and gender were independent factors that impact the survival among these patients.

慢性淋巴细胞白血病（CLL）和多发性骨髓瘤（MM）都是起源于不同分化阶段的成熟B细胞的常见血液系统恶性肿瘤。然而，在 CLL 诊断后发展成 MM 的情况非常罕见。我们报告了一名 66 岁女性在被诊断为 CLL 3 年后进展为前向性骨髓瘤，并根据监测、流行病学和最终结果 (SEER) 数据库对这些患者的流行病学和临床特征进行了分析。我们的数据表明，CLL 患者发生骨髓瘤的可能性比美国一般人群低 19%（标准化发病率 0.81；95% 置信区间 0.62-1.03），尽管没有统计学差异。诊断出 CLL 的中位总生存期为 90 (58.1-121.9) 个月，根据历史数据，这与一般 CLL 患者相同。但继发性 MM 的预后比一般 MM 患者差得多。年龄和性别是影响这些患者生存的独立因素。