Malignant Triton Tumor: Role of Electron Microscopy in Determining Differentiation

Abstract

Malignant triton tumors (MTTs) are peripheral nerve sheath tumors: Perivascular origin is extremely rare. We report a sporadic perivascular MTT in a 37-year-old man. He presented with a swelling in the right popliteal fossa. Imaging revealed a solid lesion adherent to the popliteal artery. He underwent en bloc excision of the tumor with repair of the popliteal artery. We studied the histopathology and electron microscopy (EM) features of this tumor. He received local radiotherapy and remains disease-free at 2 years. EM may help prognosticate tumor behavior when these tumors occur in rare/nonneural locations.