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.

We describe the case of a 6-year-old girl with typical infectious mononucleosis syndrome complicated by clustered right hemiconvulsions and disturbed consciousness. Diffusion-weighted magnetic resonance imaging on admission demonstrated reduced diffusion in the left temporo-posterior cortex and pulvinar of the ipsilateral thalamus. Her neurological symptoms resolved completely by the next day, with complete disappearance of abnormal signal intensities on magnetic resonance imaging (MRI). Elevated cerebrospinal fluid interleukin (IL)-6 with normal IL-10 might indicate a neuroprotective role of IL-6 rather than injury. We concluded that the MRI abnormalities could have been due to the seizure activity itself rather than Epstein-Barr virus-associated encephalitis. The recognition of transient seizure-related MRI abnormalities may help in the diagnostic approach to MRI changes in suspected encephalopathy.