A morphological mimic: An NTRK3‐rearranged spindle cell neoplasm presenting as a groin mass

Abstract

AbstractNeurotrophic receptor tyrosine kinase (NTRK)‐rearranged spindle cell neoplasms are a recently described group of soft tissue tumors. They commonly present as a painless mass on the extremities of children and young adults. They are characterized microscopically by a heterogeneous spectrum of infiltrative spindle cell proliferations, which can morphologically mimic several other spindle cell neoplasms. Their identification is vital, as they may be amenable to treatment with tyrosine kinase‐targeted therapy. This case report describes a rare NTRK3‐rearranged spindle cell neoplasm in the groin of a 29‐year‐old female and provides further clinical and morphological features of this entity.