EWSR1-SMAD3 fibroblastic tumour- WHO 2020 UPDATE.
EWSR1-SMAD3 fibroblastic tumour represents one of the new entities in which the name is determined by the involved fusion gene.
It is a benign neoplasm most often occurring in the hands and feet with a broad age range.
Morphologically it is composed of intersecting cellular fascicles of cytologically bland monomorphic spindle cells, alternating with hypocellular, hyalinised areas.
Immunohistochemically it is characterized by nuclear expression of ERG.