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Updated: May 23, 2026

Murine Model of Leukemia Relapse to Induction Chemotherapy for Acute Lymphoblastic Leukemia
Published on: October 17, 2025
Central nervous system lesions due to juvenile myelomonocytic leukemia progressed in a boy undergoing first line
Hiroko Fukushima1, Takashi Fukushima, Akiyoshi Hiraki
1Department of Pediatrics, Tsukuba University Hospital, Tsukuba, Japan. fukushima-tuk@umin.ac.jp
Abstract:
Juvenile myelomonocytic leukemia is a rare malignancy that occurs in pediatric patients. Previous reports, have described leukemic cells may infiltrate many organs, such as the lungs, skin, liver, spleen, and intestines, but not the central nervous system, although central nervous system infiltration remains a point of concern in every patient with acute leukemia. Here, we present one case of a boy with juvenile myelomonocytic leukemia who developed multiple lesions in the brain while undergoing chemotherapy with 6-mercaptopurine and cytarabine. We diagnosed the central nervous system involvement by magnetic resonance imaging, cerebrospinal fluid cytology, and the patient's clinical course. He was treated with a high dose of cytarabine and intrathecal chemotherapy, then with unrelated cord blood stem cell transplantation. He has been in a first complete remission for more than 18 months after cord blood stem cell transplantation without any neurological sequelae. In conclusion, we encountered a boy with juvenile myelomonocytic leukemia who developed central nervous system lesions under standard chemotherapy. We subsequently switched treatment to central nervous system-oriented chemotherapy, which resulted in a good clinical condition and successful cord blood stem cell transplantation.
Insights
Juvenile myelomonocytic leukemia (JMML) can rarely affect the central nervous system. This case highlights successful treatment of JMML with brain lesions using intensive chemotherapy and stem cell transplantation.
Area of Science:
- Pediatric Hematology Oncology
- Neuro-oncology
- Rare Pediatric Malignancies
Background:
- Juvenile myelomonocytic leukemia (JMML) is a rare pediatric cancer.
- Central nervous system (CNS) infiltration is uncommon but a significant concern in acute leukemia.
Observation:
- A boy with JMML developed multiple brain lesions during standard chemotherapy (6-mercaptopurine and cytarabine).
- CNS involvement was confirmed via MRI, CSF cytology, and clinical presentation.
Findings:
- The patient received high-dose cytarabine, intrathecal chemotherapy, and unrelated cord blood stem cell transplantation.
- Achieved and maintained complete remission for over 18 months post-transplant with no neurological deficits.
Implications:
- This case demonstrates that JMML can infiltrate the CNS even under standard chemotherapy.
- CNS-directed therapy followed by stem cell transplantation can lead to favorable outcomes in pediatric JMML with CNS involvement.
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