Soft tissue
Fibroblastic / myofibroblastic tumors
Fibroma of tendon sheath

Author: Komal Arora, M.D. (see Authors page)

Revised: 17 August 2016, last major update July 2012

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Fibroma of tendon sheath

Definition / General
Epidemiology
  • 60% men, ages 30 - 50 years old with nodule on fingers, hands or wrist
Case Reports
Treatment
  • Excise to relieve symptoms but preserve function, may be difficult to remove from adherent tendons
  • Benign, but up to 24% recur; does not metastasize
Clinical Images

Images hosted on other servers:

Multiple non-movable deep seated nodules on palm

Gross Description
  • Well circumscribed, small fibrous multinodular mass < 3 cm, cut surface is pale, solid and homogeneous
Micro Description
  • Well circumscribed nodules of dense fibrous tissue with occasional spindle or stellate mesenchymal cells in S or C shaped patterns
  • Cells have scant cytoplasm and elongate nuclei with evenly distributed fine chromatin
  • Often dilated or slit-like channels / clefts resembling tenosynovial spaces
  • Varies from cellular to paucicellular
  • May have bizarre tumor cells, extravasated red blood cells, but no atypical mitotic figures, no necrosis, no hyperchromasia
Micro Images

Images hosted on PathOut servers:

Multinodular proliferation

Transition from collagenous to cellular area

Fibroblasts are bland
(ruling out sarcoma) and
separated by collagen



Cellular area resembles
leiomyosarcoma or
fibrosarcoma, but these tumors
are rare in hands and feet

Extensive collagenization
of nodules produces this typical,
eosinophilic, paucicellular
appearance, incomplete
separation of the nodules
produces cleft-like spaces

Most cases are
paucicellular with scattered
spindled fibroblasts in a
densely collagenized matrix
and scattered small vessels

Electron Microscopy Description
  • Resembles myofibroblasts and fibroblasts
Electron Microscopy Images

Images hosted on other servers:

Various images

Positive Stains
Molecular / Cytogenetics Description
Differential Diagnosis
  • Sarcoma: rare in hands and feet, usually large masses with cellularity, marked chromatin abnormalities and abnormal mitotic figures
  • Benign fibrous histiocytoma: usually not hands or feet, prominent histiocyte-like cells, foam cells, giant cells and hemosiderin, CD68+
  • Giant cell tumor of tendon sheat: more cellular, cells have histiocyte-like nuclei, also prominent giant cells, foam cells, hemosiderin; no slit-like vascular spaces, no extensive hyalinized stroma
Additional References