NTRK3 and congenital fibrosarcoma: In addition to secretory carcinomas occurring in the breast, salivary gland [14] and thyroid [18], ETV6-NTRK3 gene fusion is also encountered in several neoplasms, including ALK-negative inflammatory myofibroblastic tumors, the cellular variant of congenital mesoblastic nephroma, congenital fibrosarcoma and radiation-induced papillary thyroid carcinoma [19, 20].