B-lymphoblastic leukemia/lymphoma arising in treated plasma cell myeloma: A rare second malignancy

Abstract

Plasma cell myeloma (PCM) is a neoplasm of plasma cells, end-stage post germinal center B cells, which shows a variable clinical spectrum from asymptomatic to aggressive; the nature of the disease is generally progressive. Rarely, leukemia arises treated plasma cell myeloma. Acute myeloid leukemia/Myelodysplastic syndrome (AML/MDS) is most common, but rare cases of B lymphoblastic leukemia/lymphoma (B-ALL) have been described. The diagnosis of transformation or secondary B-ALL is supported by ancillary studies such as flow cytometry, immunohistochemistry, and molecular studies. Once the diagnosis of a B-ALL is made, consideration should is given as to whether the malignancy is a clonally related transformation of the original PCM or treatment related second leukemia. We present a case of B-ALL after PCM which does not appear to show a clonal relationship with the original PCM suggesting a treatment related B-ALL. Keywords: Plasma cell myeloma, Treatment related acute leukemia, Transformation, B-lymphoblastic leukemia/lymphoma, Molecular clonality