Clinicopathological findings of pediatric NTRK fusion mesenchymal tumors

Figures

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  Fig. 1. a-e Case 1 with TPR-NTRK1 fusion.: MRI reveals a) T1-low, b-d) T2-high dura-based mass with enhancement. e The tumor was located in the right temporal convexity and right cerebellar tent (The direction of the brain mentioned as cephalhead and posterior). The inlet is the cut surface of the tumor showing yellowish, and solid without hemorrhage or necrosis. f, g Case 2 with LMNA-NTRK1 fusion tumor: T2 weighted MRI revealed low-density mass on the left forehead. The cut surface of the tumor shows a gray-white solid appearance without hemorrhage or necrosis

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  Fig. 2. a Chest CT of the ETV6-NTRK3 fusion-positive inflammatory myofibroblastic tumor (IMT) reveals a heterogeneously enhancing tumor in the left lower part of the thorax. b The mass arises from extrapulmonary sequestration, supplied by the left phrenic artery, which is separated from the lower lobe of the lung. c The cut surface of the tumor is hemorrhagic and has congested large vessels. d This is the microscopic picture of the squared part of Fig. c. It is a well-encapsulated, but partly adhered to the lower lobe of the left lung. The tumor pushed the left lower lobe of the lung. Hemorrhage was developed by previous embolization of large vessels of the sequestrated lung, under the impression of arteriovenous malformation

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  Fig. 3. a Histology of the intracranial undifferentiated sarcoma with TPR-NTRK1 fusion shows alternating cellular areas with collagen bands show a tiger pattern-like appearance. The tumor cells are oval to short spindle cells. b The forehead mesenchymal tumor with LMNA-NTRK1 fusion shows relatively low cellular spindle cell mesenchymal tumor with keloid type collagen laydown. c The pulmonary inflammatory myofibroblastic tumor with ETV6-NTRK3 fusion shows bland-looking spindle cells with intermixed lymphoplasma cells. d A sacrococcygeal infantile fibrosarcoma with ETV6-NTRK3 fusion shows fascicular spindle cells with high cellularity (a-d: H&E, bar: a: 300, μm, b-d: 50 μm)

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  Fig. 4. a, b Sarcoma with TPR-NTRK1 fusion shows co-positive for nestin and CD34. c, d ETV6-NTRK3 fusion-positive infantile fibrosarcoma is co-positive for S100 protein and CD10. e-h The LMNA-NTRK1 fusion sarcoma has lots of CD3-positive T-cell infiltration and robustly coexpressed CD34, S100, and CD10. (a: nestin, b, f: CD34, c, g: S100 protein, e: CD34D, h: CD10, Bar: 200 μm)

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  Fig. 5. Trk immunohistochemistry shows a Nuclear positivity in TPR-NTRK1 fusion sarcoma (Case 1), b mostly nuclear membrane, and cytoplasmic stain in LMNA-NTRK1 fusion sarcoma (Case 2). and c mainly cytoplasmic stain in ETV6-NTRK3 fusion sarcoma. In Fig. b, the Trk-negative cells are infiltrating inflammatory cells (a-c: Trk IHC, lower bar: 50 μm). d. locus-specific identifier (LSI) FISH study using ETV6 fluorescence dual-color break apart DNA probes show one fused and one widely separated SpectrumGreen and SpectrumOrange signals in an infantile fibrosarcoma with ETV6-NTRK3 fusion-positive

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  Fig. 6. The custom NGS panel revealed TPR-NTRK1 fusion (IGV capture)