UPDATE ARTICLES/COMMENTARIES: PDF OnlyParachordoma Exists - But What Is It?Fisher, CyrilAuthor Information On: Parachordoma is immunohistochemically and cytogenetically distinct from axial chordoma and extraskeletal myxoid chondrosarcoma. Folpe AL, Agoff SN, Willis J, Weiss SW. Am J Surg Pathol 1999;23:1059-67 At the Royal Marsden Hospital, London, United Kingdom. Advances in Anatomic Pathology: May 2000 - Volume 7 - Issue 3 - p 141-148 Buy Abstract Summary: Parachordoma is a very rare peripheral soft tissue tumor of unknown lineage, which has been described under other names, all of which imply a similarity to chordoma. It forms a circumscribed firm tumor, usually in deep soft tissue, with a variety of histologic patterns and cytologic features, including cords and nests of cells, some of which are vacuolated. The ultrastructure and immunophenotype indicate epithelial differentiation and parachordomas are additionally S-100 protein positive. This tumor is distinct from extraskeletal myxoid chondrosarcoma and probably from soft tissue myoepithelioma. While histologically it somewhat resembles chordoma, parachordoma has a wider range of appearances, and the two neoplasms differ in their detailed cytokeratin immunophenotype and their clinical behavior. Parachordoma is a slowly growing tumor with occasional late recurrence; cases with reported metastasis have not been histologically convincing. This commentary discusses the terminology, origin, and possible nature of this enigmatic neoplasm. © 2000 Lippincott Williams & Wilkins, Inc.