Spontaneous regression of aleukaemic cutis leukaemia in a male infant

Abstract Introduction Congenital leukaemia is a rare haematologic disease presenting in the first 4-6 weeks of life. Affected children may present with systemic symptoms of fever, hepatosplenomegaly and skin infiltration in the form of leukaemia cutis. Prognosis is generally poor but some cases of spontaneous regression have been described. We report a case of a 5-week-old who had biopsy confirmed cutis leukaemia which went on to resolve spontaneously. Case A male infant developed widespread erythematous/violaceous patches and nodules in the first week of life. He remained systemically well. A skin biopsy at 5 weeks of age showed features of a malignant haematological infiltrate, favouring a myeloid/monocytic leukaemic process. Baseline bloods were normal including a blood film which did not show any evidence of blasts. Interestingly, following his biopsy, skin lesions began to improve with complete resolution of all skin lesions by six weeks of age. RNA fusion panel analysis of affected skin detected a PICALM::MLLT10 t(10;11) (p12;q14) fusion which is a rare but recurrent finding in acute lymphoblastic leukaemia . He continues monthly haematology surveillance and has remained disease free at 8 months. Conclusion Spontaneous regression of aleukaemic leukaemia cutis is a rare phenomenon. Patients require close ongoing surveillance as some may relapse with systemic disease after several years. Key to management of this case was prompt suspicion of leukaemia cutis and biopsy which enabled an accurate diagnosis despite the brief window of skin lesions and has subsequently enabled accurate genotyping and future rigorous surveillance in this child.