Fig 2: Muscle biopsy findings. A, B Hematoxylin & eosin staining showing dense endomysial lymphocytic aggregates (A), and perimysial fragmentation with plasma cell-rich perivascular infiltrates (B). C–F Immunohistochemical stains showing endomysial aggregates composed of predominant CD20 + B cells (C) and accompanying CD3 + T cells (D); diffuse upregulation of MHC class I (E); and perifascicular upregulation of MHC class II (F). Bar, A–D 50 µm (× 20 objective); E–F 100 µm (× 10 objective). Method for picture acquisition: Olympus BX46 microscope, with UPlanFL objectives with CellSens software (Olympus). The six images were placed in photoshop, in a 600dpi canvas, without further processing, to organize them and include lettering and bars. The final panel was exported as a jpg with 80% quality setting

Fig 3: Core needle biopsy specimen showing tumor heterogeneity with high cellularity on the left and stromal collagenization on the right (A). Higher magnification image demonstrates a high-grade pleomorphic sarcoma with severe nuclear atypia (B). Microscopy was performed using an Olympus BX46 microscope with UPlanFL N lenses and an Olympus DP73 camera with no filter; acquisition software was Olympus cellSens standard with a resolution of 4800 (W) × 3600(H) pixels and no downstream processing

Fig 4: Combining sorafenib with ATO induces strong apoptosis, cell cycle arrest and differentiation in FLT3/ITD+ cell linesA. FLT3/ITD+ (Molm14, MV4;11) cells were treated with sorafenib/quizartinib +/- ATO at the indicated concentrations followed by Annexin V binding 24 or 48 hours later. B. For cell cycle analysis, cells were stained with propidium iodide (PI) at 48h followed by flow cytometry. C. FLT3/ITD+ (Molm14, MV4;11) leukemia cell lines were treated with sorafenib and / or ATO at the indicated concentrations followed by CD11b staining and flow cytometry analysis 48 hours after treatment. D. Cellular morphology 48 hours after sorafenib (8nM) and / or ATO (2µM) treatment (500× images, scale bar = 10 microns; 1000× images, scale bar = 20 microns). Wright-Geimsa stained slides were imaged on an Olympus BX46 microscope with an Olympus DP72 camera using Olympus cellSens Standard 1.5 image acquisition software. E. C/EBPa and PU.1 expression, determined by Quantitative RT-PCR as normalized to GAPDH, and F. Western blotting for C/EBPa and PU.1 expression in Molm14 cells following 48-hour treatment with ATO at the indicated concentrations.

Fig 5: I, II: A chest CT at week 2 showed patchy ill-defined consolidations and areas of ground glass opacifications in the periphery of both lower lobes, mostly pronounced in the left lower lobe and subtle thickening of the bronchial walls; III, IV: Progression of the ground glass opacities and consolidations in both lower lobes as well as mediastinal lymphadenopathy on chest CT at week 6; V, VI: Chest CT at week 8: extensive diffuse opacification of both lungs with a ventro-dorsal density gradient with ground glass opacities in the non-dependent regions of the lungs and consolidations in the dependent regions, compatible with a diffuse alveolar damage. There was no evidence of pneumomediastinum. Clinically, the patient fulfilled criteria of an ARDS and was on ECMO; VII: Fibreoptic bronchoscopy showing multiple white nodular plaques, spanning from the larynx throughout most of the bronchial tract at week 4; VIII: Significant progression of organizing pneumonia with DAD, diffuse leukoplakia and acute bronchitis with complete squamous metaplasia at week 6; a, b: Histopathology of the lung-explant (H&E staining × 400): Acute lung damage with focal signs of organization; a: Features of organizing DAD and organizing pneumonia; b: Trichrome stain shows alveolar fibrin deposits (so-called hyaline membranes, arrowheads). The lung histopathology slides were observed in an Olympus BX46 microscope with a Pan XApo 10 × objective (final magnification 400x). Representative areas were selected, and images taken with a ProgRes C5 camera (Jenaoptik) and the corresponding ProgRes MacCapture Pro Application (2013). Except for illumination adjustment (Autofocus mode) no further enhancements of pictures were deemed necessary