Soft tissue
Extraskeletal bone tumors
Parachordoma
Author: Vijay Shankar, M.D.
Topic Completed: 1 November 2012
Minor changes: 20 November 2020
Copyright: 2002-2021, PathologyOutlines.com, Inc.
PubMed Search: Parachordoma
Table of Contents
Definition / general | Case reports | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Molecular / cytogenetics description | Differential diagnosisCite this page: Shankar V. Parachordoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/softtissueeskparachordoma.html. Accessed January 22nd, 2021.
Definition / general
- Rare (< 50 cases reported) soft-tissue tumor resembling extraskeletal myxoid chondrosarcoma and chordoma
- Develops next to tendon, synovium, osseous structures in extremities
- Mean age 35 years, range 7 - 62 years
- Surgical excision usually adequate
Case reports
- 28 year old man with mass and pain in shoulder (Turk Patoloji Derg 2011;27:173)
- 48 year old woman with mild intermittent lower abdominal distending pain (Rare Tumors 2012;4:e5)
- 60 year old woman with upper arm mass (Clin Orthop Relat Res 2008;466:1251)
Microscopic (histologic) description
- Well circumscribed lobules of large, round and eosinophilic cells, focally resembling physaliferous cells or cartilaginous cells in myxoid to densely hyaline matrix
- Also spindle cells
Microscopic (histologic) images
Images hosted on other servers:
Presacral tumor
Upper arm
Positive stains
Negative stains
Molecular / cytogenetics description
- Trisomy 15 (one case), monosomy 1, 16, 17
Differential diagnosis
- Chordoma: many multivacuolated (physaliferouslike) cells; monosomy 3, 4, 10 or 13; type 4 collagen negative (Am J Surg Pathol 1999;23:1059)
- Extraskeletal myxoid chondrosarcoma: t(9;22)+, type 4 collagen negative
