NTRK1 and neoplasm with perivascular epithelioid cell differentiation: Two cases with malignant TFE3-rearranged PEComa showed treatment response with the antivascular endothelial growth factor (VEGF) receptor tyrosine kinase inhibitor apatinib, suggesting that VEGF signaling may also be implicated in TFE3-associated PEComas (46, 47).