An unusual case of chronic lymphocytic leukemia with trisomy 12 presenting with prolymphocytic transformation and t(8;21)(q22;q22).

First report of t(8;21)(q22;q22) in a patient with CLL. RUNX1-RUNX1T1 fusion gene resulting from the translocation may have played a role in the prolymphocytic transformation.

An 81‐year‐old man with 20‐year history of chronic lymphoid leukemia/small lymphocytic lymphoma (CLL/SLL) with trisomy 12 presented with weakness. CBC showed WBC 60.2 × 109 cells/L, hemoglobin 13.2 g/dL, and platelet count of 95 × 109 cells/L. Imaging revealed lymphadenopathy and splenomegaly. Peripheral blood and marrow aspirate showed prolymphocytes (Figure 1A‐B). Cytogenetics showed a t(8;21)(q22;q22.1) and trisomy 12 in six out of twenty metaphases (Figure 2A).

FIGURE 1

Peripheral blood showing prolymphocytic transformation to CLL cells (1A) and bone marrow biopsy with transformation of CLL to prolymphocytic leukemia (1B)

FIGURE 2

Cytogenetics showed an abnormal male karyotype with six out of twenty metaphases showing a translocation between chromosomes 8 and 21 in addition to trisomy 12 (2A)

Chronic lymphoid leukemia/small lymphocytic lymphoma is an indolent lymphoproliferative disorder that can transform into an aggressive malignancy with unfavorable prognosis in about 5%‐10% of patients. , Transformation can be prolymphocytic or into diffuse large cell lymphoma, also known as Richter transformation. , , , , There are no known cases to date of transformation to prolymphocytic leukemia with t(8;21)(q22;q22.1), which is typically observed in acute myeloid leukemia. , The t(8;21) results in a fusion oncoprotein between RUNX1 and ETO. RUNX1‐RUNX1T1 fusion leads to disruption of normal function of the core‐binding factor in the regulation of hematopoietic differentiation and maturation. Given that RUNX1 is critical for maturation of a wide range of hematopoietic stem cells and has been implicated in pathogenesis of several myeloid and lymphoid malignancies, we postulate that the t(8;21)(q22;q22.1) played a role in prolymphocytic transformation in this patient. , ,

CONFLICT OF INTEREST

None.

AUTHOR CONTRIBUTIONS

I, MB: am the first author of this publication, and KRK: is the advising author of this publication.