A Favourable Outcome in a Congenital Leukaemia Patient With Unique Cytogenetic Abnormalities

Abstract

Congenital leukaemia (CL) is an exceptionally uncommon hematologic malignancy originating intrauterine and is typically associated with an unfavourable prognosis. The present case is a seven-day-old Malay baby girl who presented with mild fever and hepatosplenomegaly. She was initially treated as neonatal sepsis however subsequent investigations with bone marrow, trephine biopsy and immunophenotyping were consistent with B acute lymphoblastic leukaemia. The peripheral blood smear showed the presence of 90% blast cells. Cytogenetically, she harboured an unusual complex karyotype, 46,XX,der(5) t(5;15)(p15;q15),del(7)(q33q35)/47,idem,+2.ish t(5;15)(wcp15+)+22(wcp22+). This rare case with extremely atypical cytogenetic findings is being brought to light since the patient responded favourably to the standard chemotherapy Interfant 06 protocol, during which she obtained many episodes of remission, and she still survives after three years of treatment. Despite that, she carries del(7), which is normally associated with adverse outcomes in myeloid disorders, but not in lymphoid disorders; the existence of t(5;15)(p15;q15) could be the element that contributes to her fortunate outcome. Although trisomy 22 is identified as a clonal abnormality, its significance in her case and lymphoid disorders remains unknown and requires further investigation.

Keywords: b acute lymphoblastic leukaemia; congenital leukaemia; del(7)(q33q35); t(5:15); trisomy 22.

Figure 1. Patient’s bone marrow karyogram shows first abnormal clone with 46,XX,der(5)t(5;15)(p15;q15),del(7)(q33q35)

Figure 2. Patient’s bone marrow karyogram showing second abnormal clones with 47, XX der(5)t(5;15)(p15;q15),del(7)(q33q35),+22

Figure 3. Partial karyotypes from bone marrow metaphases showing translocation between chromosome 5 and 15 and del(7)(q33q35)

Figure 4. Metaphase fluorescence in situ hybridization (FISH) images of whole chromosome painting probes (WCP) for chromosome 15 showed the presence of three signals for chromosome 15 and three signals for chromosome 22 to confirm the t(5;15) and trisomy of chromosome 22 (trisomy 22).