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Acute myeloid leukaemia (AML) with t(6;11)(q27;q23), resulting in a chimeric MLL/AF6 gene, is rare (≤0.6% of adult cases),1 ,2 and is associated with poor prognosis.2 ,3 The majority of these cases are acute myelomonocytic leukaemia, or acute monoblastic/monocytic leukaemia,1 and they have increased risk for hyperleukocytosis requiring leukapheresis.4 The RAS association domain (RA1) at the N-terminus of AF6 is sufficient for MLL-AF6 to mediate leukemogenesis.5 Although an activated KRAS mutation accelerates MLL/AF4-driven leukemogenesis in transgenic mice,6 whether it will do the same with MLL/AF6 is unknown. Here, we report a rare and aggressive case of acute monocytic leukaemia with both MLL/AF6 and KRAS G12D.
A middle-aged man in his 40s had sore throat, chills, night sweats and swelling in the neck for four days prior to presentation to a local emergency centre. Concurrently, non-pruritic purple skin lesions appeared on his body. A complete blood count showed a white blood cell (WBC) count of 3 25 000/mm3, a platelet count of 60 000/mm3, and 92% monocytes in the blood smear. He was given 6 g of hydroxyurea orally and transferred to a tertiary cancer centre for emergent treatment of hyperleukocytosis. His past medical history, social history and family history were non-contributory.
Upon arrival at the cancer centre, he became dyspneic. His vital signs were: blood pressure 107/53 mm Hg; heart rate …