case_images: PMC11754338_01
case_images: Presentation and primary treatment imaging. Non-contrast CT demonstrated what was initially thought to represent a right MCA thrombus occlusion (panel A arrow). MR imaging 1 day later demonstrated increased oedema on axial T2 sequences and associated diffusion restriction in an MCA distribution on the ADC map (panels B and C respectively, arrows). Yet, no major vessel occlusion was seen on the time-of-flight MRA (panel D). Panels E-H are taken from the re-presentation MRI scan some 5 weeks later. Axial T2 sequences showed worsening oedema (panel E, arrow). The T1 post-contrast image (panel F) showed significant leptomeningeal thickening and enhancement (white arrow) but no mass lesion. Concurrent ASL demonstrated significantly increased perfusion mapping to the leptomeningeal disease (panels G and H, arrows). By the end of therapy, the axial T2 (panel I) showed a reduction in peri-sylvian oedema (arrow) with a resolution to the previously seen contrast enhancement (panel J, arrow). This area also demonstrated post-treatment volume loss. The ASL sequence shows resolution to the previously seen increased perfusion (panel K, arrow, versus G and H; see Supplementary Information)
case_images: 381_2024_6698_Fig1_HTML.jpg
case_images: PMC11754338_01_381_2024_6698_Fig1_HTML.jpg
case_images: Fig1
case_images: However, MR angiography failed to identify the occlusive disease (Fig. 1A-D). There was no discernible mass lesion (Fig. 1E-H). The previously seen enhancing leptomeningeal disease, diffusion restriction and increased perfusion changes had resolved (Fig. 1I-K).
case_images: Morphology and molecular biology. Histological morphology reveals tumour rhabdoid cells arranged in sheets within a myxoid stroma, moderate eosinophilic cytoplasm, vesicular nuclei and pleomorphism (A 40 x magnification). Mitotic activity was high. Tumour cells revealed intranuclear loss of INI1 (B 20 x magnification). Copy number analysis (C) from the Illumina Epic Methylation array reveals loss of chromosome 22, housing SMARCB1 (black arrow). Subsequent unsupervised clustering of expanded paediatric tumour reference samples (n = 1200) against patient samples by t-distributed stochastic neighbour embedding (tSNE) dimensionality reduction analysis is shown (D). Individual samples are colour-coded in the respective tumour class. Red circle outlines indicate samples from the same batch of data
case_images: 381_2024_6698_Fig2_HTML.jpg
case_images: PMC11754338_01_381_2024_6698_Fig2_HTML.jpg
case_images: Fig2
case_images: Histological examination diagnosed ATRT with highly cellular tumour infiltrating parenchyma (Fig. 2A). Tumour cells were positive for EMA but revealed intranuclear loss of INI1 (Fig. 2B). Mb) incorporating SMARCB1 and extending upstream to TBX and downstream to NIPSNAP1. Methylation array profiling (Supplementary Information; Fig. 2C, D) confirmed both chromosome 22 loss and ATRT-MYC subgrouping.
case_images: Presumed relapse and recovery imaging. At 4 months post-therapy, there was increasing ASL perfusion overlying the left cerebral hemisphere (panel A, white arrows). By 8 months, the axial T1 post-contrast imaging demonstrated increasing leptomeningeal enhancement in this distribution (panel B, white arrow). At the same timepoint, there was extensive spinal nodular disease (panel C, white arrow) as well as disease seen coating the whole of the spinal cord (panel C, white arrowhead). Following the cessation of therapy and initiation of palliative care, there was a significant improvement in imaging appearances. The leptomeningeal enhancement resolved (panel E, white arrow) and the degree of increased perfusion significantly improved (panel D, white arrow), although it never returned to baseline. The apparent spinal disease completely resolved (panel F)
case_images: 381_2024_6698_Fig3_HTML.jpg
case_images: PMC11754338_01_381_2024_6698_Fig3_HTML.jpg
case_images: Fig3
case_images: However, at 4 months post-therapy, imaging appearances had declined, initially with increasing perfusion overlying the left cortical mantle (Fig. 3A). This was gradually accompanied by corresponding increased diffusion restriction and leptomeningeal enhancement (Fig. 3B). By 8 months post-therapy, the patient had developed worsening of presumed neuraxial nodular and leptomeningeal disease coating the left cerebral hemisphere, spine and posterior fossa (Fig. 3C). Repeat imaging 6 months following palliation showed resolution of almost all abnormalities in the brain and spine (Fig. 3D-F).