Other benign / low grade tumors

Topic Completed: 1 December 2012

Revised: 13 February 2019

Copyright: 2003-2018,, Inc.

PubMed Search: Fibromatosis mediastinum

Hanni Gulwani, M.B.B.S.
Page views in 2018: 99
Page views in 2019 to date: 158
Cite this page: Gulwani H. Fibromatosis. website. Accessed September 16th, 2019.
Definition / general
  • Anterior or posterior mediastinum
  • Children and young adults
Clinical features
  • Associated with superior vena cava syndrome, nerve entrapment or dysphagia
Case reports
Gross description
  • Poorly demarcated (often receive in multiple fragments), gritty, tan-white, centered in soft tissue
Microscopic (histologic) description
  • Fibromyxoid matrix with paucicellular, bland tumor cells in parallel or fascicular patterns
  • Cells have dispersed chromatin, minimal nucleoli, eosinophilic or amphophilic cytoplasm
  • Thick walled venule sized vessels with open lumina
  • No staghorn vessels
  • No storiform growth, no nuclear pleomorphism, no / rare mitotic activity, no inflammatory infiltrate
Microscopic (histologic) images

Images hosted on other servers:

A: fusiform cells; B: myxoid degeneration

Positive stains
Electron microscopy description
  • Myofibroblastic features of intrareticular collagen fibers, thin filament bundles, cytoplasmic dense bodies
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