Unique Presentation of Autoinflammatory Disease-like Symptoms and Development of Leukemic Cell Lysis Pneumopathy in Childhood KMT2A::LASP1-positive Acute Monocytic Leukemia

In the literature, long-term autoinflammatory disease (AID)-like symptoms are extremely rare in childhood acute leukemia cases. Here, we report a 14-month-old girl with KMT2A::LASP1 -positive acute monocytic leukemia diagnosed after a 7-month course of AID-like symptoms. KMT2A::LASP1 fusion was retrospectively detected in her bone marrow at the initial presentation of AID-like symptoms, suggesting the involvement of leukemia cells in her AID-like symptoms. Immediately after starting chemotherapy, the patient sequentially developed leukemic cell lysis pneumopathy (LCLP), which was successfully overcome by the continuation of chemotherapy under intensive respiratory support, thus suggesting a possible association of her AID-like symptoms with the development of LCLP.