Fig. 3: High-grade spindle-cell sarcomas with NTRK1 rearrangements.

a Highly infiltrative malignant spindled cell tumor (case 7). Some areas showed myxoid stroma generating an epithelioid or round-cell morphology (b). Case 8 demonstrated transition from low-grade spindle-cell areas (c) to high-grade areas resembling pleomorphic sarcoma (d).