Synchronous dual hematological malignancies: new or underreported entity?

BACKGROUND: Patients with a single hematological malignancy may be unexpectedly diagnosed with a clonally unrelated synchronous dual hematological malignancy (SDHM). The presence of a secondary hematological malignancy may be overlooked and only identified in situations presenting with discordant clinical or laboratory findings. Clinical management of these patients can be challenging, in part due to the relatively unknown etiopathology of SDHM and the impact of therapy on the secondary malignancy. OBJECTIVES: To assess, characterize patients with synchronous double hematological malignancies and share our experience with this challenging group of patients. METHODS: We performed a retrospective chart review of 3036 patients with hematological malignancy at our cancer center between February 2013 and July 2017. RESULTS AND DISCUSSION: We identified 46 patients with SDHM, a prevalence of 1.51% among patients diagnosed with any hematological malignancy. We identify several heterogeneous combinations of SDHM comprised of myeloid and/or lymphoid lineages and provide our experience with managing patients with these underreported conditions. CONCLUSION: SDHMs are not uncommon and should be suspected in situations presenting with unusual or unexpected findings.