case_images: PMC9603755_01
case_images: CT and MRI findings for Patient one. A large abnormal signal mass (5.4 cm x 5.7 cm x 7.0 cm) was detected above the cerebellum in the posterior fossa, with poorly defined borders. CT showed a slightly high-density mass shadow. T1WI revealed isointense or low signal, T2-FLAR isointense or slightly high signal, and DWI high signal. Enhanced scanning showed high heterogeneity (multiple nodules). There was no obvious abnormality regarding the spinal cord or morphological signals; the surface of the spinal cord was line-like, with small, strong nodular signals by enhanced scanning. (A): Preoperative, noncontrast CT. (B): DWI. (C) and (D): Gd-enhanced T1W images. (E): Gd-enhanced MRI of the spinal cord.
case_images: fonc-12-988798-g001.jpg
case_images: PMC9603755_01_fonc-12-988798-g001.jpg
case_images: f1
case_images: T1WI, iso- and slight hyperintensity on T2-FLAIR, and hyperintensity on DWI, with a size of approximately 5.4 cmx5.7 cmx7.0 cm. There were multiple strong nodular contrast-enhanced signals, obvious compression of the brainstem, compression and narrowing of the fourth ventricle, and obvious enlargement of the supratentorial ventricle ( Figure 1 ). By comparing with the head MRI of Patient two ( Supplementary Figure 1 ), the tumor morphological characteristics of the two boys were very similar.
case_images: Gene copy number variation (CNV) in Patient one. Copy number was evaluated as the normal copy number: 2, increased 2> and decreasing copy number <2. BRCA1 (3.3,Gain), SMARCA4 (3.0, Gain), SMARCB1 (1.1,Loss), STK11 (3.0,Gain), TP53 (3.3,Gain), and ERBB2 (3.3,Gain).
case_images: fonc-12-988798-g002.jpg
case_images: PMC9603755_01_fonc-12-988798-g002.jpg
case_images: f2
case_images: Postoperative head CT and enhanced MRI re-examination indicated satisfactory tumor resection (gross total resection) ( Supplementary Figure 2 ). TP53 (gain) (see  Figure 2  for CNV variation information). The distribution of mutations in Patient one is illustrated by a Circos diagram in  Supplementary Figure 4 .