case_images: PMC6761274_01
case_images: The chemotherapy process of the patient based on the Chinese Children's Cancer Group ALL 2015 (CCCG-2015-ALL) protocol. The red arrow represents the time of developing intracranial hemorrhage at the start of maintenance therapy. Dasatinib was given when neutrophil count was more than 1x109/L with platelet count more than 50x109/L. Maintenance therapy methotrexate (MTX) was given respectively at day 1 and day 8 with oral daily mercaptopurine (6-MP) for 14 days; cyclophosphamide (CTX), vindesine (VDS), cytarabine (Ara-C), and intrathecal therapy (I.T.) were given at day 15 monthly with oral dexamethasone (Dex) from day 15 to day 22.
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case_images: The process of chemotherapy is shown in  Figure 1 .
case_images: Clinical presentation of the patient during the first course of high-dose methotrexate (HD-MTX). MTX concentrations were monitored closely at 44, 68, 72, and 96 h after MTX infusion until the target level was reached. The patient developed vomiting, diarrhea, and cholecystitis at day 4 after infusion. The highest level of serum alanine aminotransferase (ALT) occurred at day 7. Dasatinib was withdrawn at the onset of vomiting and diarrhea.
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case_images: The clinical presentation is shown in  Figure 2 .
case_images: Clinical presentation of the patient during the second course of HD-MTX. MTX concentrations were monitored closely at 44, 68, 72, and 96 h after MTX infusion until the target level was reached. Skin toxicity appeared at day 8, with the highest level of serum ALT appearing day 10 after HD-MTX infusion. Dasatinib was withdrawn at the onset of rashes.
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case_images: He was admitted again for myelosuppression, oral mucositis, rashes, and liver dysfunction.  Figure 3  shows the clinical presentation during his second course.
case_images: Dermatologic toxicity after treatment with HD-MTX. The patient developed skin erosions that were distributed over his face and arms (A and B). Fading rashes and hyperpigmentation appeared after treatment (C and D). Written informed consent for the publication of this image was obtained from the parents of the patient.
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case_images: The most serious side effect was mucocutaneous toxicity, featuring dental ulcers and itchy erythema distributed over his face, arms, and trunk ( Figure 4 ).
case_images: Brain computed tomography (CT) of the patient after oral low-dose MTX. Multiple hematomas were shown involving the left frontal (A), parietal (B), and temporal lobes (C) and the centrum semiovale (D).
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case_images: CT scan of his brain showed increased densities that were associated with multiple hematomas in the left frontal, parietal, and temporal lobes and the centrum semiovale ( Figure 5 ). CT cerebral angiography was performed to rule out intracranial aneurysm.