A case of NTRK-rearranged neoplasm

1. Coexpression of S100 and CD34 by immunohistochemistry is the key.

2. These tumors exhibit a broad range of morphologies and histological grades. They are characterized by disorganized arrangements of monomorphic spindle cells, infiltrative growth into fat resembling lipofibromatosis, and the presence of distinctive stromal and perivascular keloid-like collagen.