Low-grade fibromyxoid sarcoma mimicking solitary fibrous tumor: a report of two cases

Virchows Arch. 2015 Feb;466(2):223-8. doi: 10.1007/s00428-014-1684-5. Epub 2014 Nov 23.

Abstract

Low-grade fibromyxoid sarcoma (LGFMS) is an uncommon fibroblastic neoplasm with many morphologic mimics. Solitary fibrous tumor is a more common fibroblastic neoplasm, but the two rarely enter the same differential diagnosis. However, here, we report two unusual cases of LGFMS, containing dilated, hemangiopericytoma-like blood vessels, which prompted diagnostic considerations of solitary fibrous tumor. Both cases presented were confirmed to harbor FUS gene rearrangement, thereby confirming a diagnosis of LGFMS. One case is that of an 18-year-old male with a left forearm mass, and the other a 50-year-old man with a left popliteal mass. While both cases show some histologic features of LGFMS, the non-classical, dilated blood vessel pattern seen here may serve as a diagnostic pitfall, as LGFMS normally exhibits fine, curvilinear blood vessels. To our knowledge, there is only one other report of LGFMS displaying such hemangiopericytoma-like blood vessels. In summary, when encountering a bland spindle cell neoplasm with classic hemangiopericytoma-like blood vessels, it is prudent to consider a diagnosis of LGFMS besides solitary fibrous tumor--particularly in the absence of CD34 immunoreactivity as it may be a rare, mimicking variant of LGFMS.

Publication types

  • Case Reports

MeSH terms

  • Adolescent
  • Biomarkers, Tumor / analysis
  • Biomarkers, Tumor / genetics
  • Biomarkers, Tumor / metabolism
  • Diagnosis, Differential
  • Fibroma / diagnosis*
  • Fibroma / genetics
  • Humans
  • In Situ Hybridization, Fluorescence
  • Male
  • Middle Aged
  • Sarcoma / diagnosis*
  • Sarcoma / genetics
  • Soft Tissue Neoplasms / diagnosis*
  • Soft Tissue Neoplasms / genetics
  • Solitary Fibrous Tumors / diagnosis*
  • Solitary Fibrous Tumors / genetics
  • Tumor Suppressor Proteins / genetics

Substances

  • Biomarkers, Tumor
  • TUSC2 protein, human
  • Tumor Suppressor Proteins