Stanford School of Medicine
Surgical Pathology Criteria
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Fibroma of Tendon Sheath


  • Lobular, circumscribed fibroblastic process of the extremities

Diagnostic Criteria

  • Circumscribed, frequently multinodular
    • Usually densely collagenized, paucicellular
    • Occasionally predominantly or entirely cellular with scant collagen
  • Bland spindled or stellate cells
    • Uniform, elongate nuclei
      • May be large and vesicular or small and dense
      • Chromatin even, fine to dense
    • Rare cases with pleomorphic cells
      • Scant mitotic figures
      • Designated "Pleomorphic fibroma of tendon sheath"
      • No clinical significance
  • Mitotic figures present but not atypical
  • Rarely over 2 cm, never over 6 cm
  • Cellular areas may have features of nodular fasciitis
    • Undulating bundles of cells
    • Myxoid areas
    • Extravasated RBCs
  • Usually attached to tendon or tendon sheath
  • Slit-like vascular spaces may be frequent
  • Absent to rare findings
    • Histiocytes
    • Xanthoma cells
    • Hemosiderin, free or in macrophages
    • Multinucleated giant cells
      • A few may be seen in rare cases

    Richard L Kempson MD
    Robert V Rouse MD
    Department of Pathology
    Stanford University School of Medicine
    Stanford CA 94305-5342

    Original posting: October 15, 2007
    Last Update: March 16, 2008

Supplemental studies


Vimentin Strong diffuse positive
Smooth muscle actin Strong diffuse positive
CD34 Positive (few cases)
CD68, CD163 Focal
Desmin Negative
S100 Negative
Beta-catenin Negative

Differential diagnosis

Tenosynovial Giant Cell Tumor Fibroma of Tendon Sheath
Oval histiocyte-like nuclei Elongate nuclei
Giant cells nearly always present Giant cells rare
Foamy histiocytes common Histiocytes rare
Hemosiderin common Hemosiderin rare
No slit-like vascular spaces Slit-like vascular spaces common
Smooth muscle actin negative Smooth muscle actin strong positive
Desmin may be positive Desmin negative


Fibroma of Tendon Sheath Inclusion Body Fibromatosis
Most common in adults Vast majority very young
Usually densely collagenized Usually cellular
No inclusions Inclusions usually present


Nodular Fasciitis Fibroma of Tendon Sheath
Rare on hands Most on hands
Rapid growth Slow growth
Not circumscribed Circumscribed
Virtually no recurrences May recur
Although fibroma of tendon sheath is typically sclerotic and nodular fasciitis is typically not, there is sufficient variation in patterns to cause overlap. Most such lesions on the hands are labeled fibroma of tendon sheath.


Desmoplastic Fibroblastoma Fibroma of Tendon Sheath
Wide distribution Most on hands or wrist
Single nodule Multilobular
Hypovascular Moderately vascular


Palmar or Plantar Fibromatosis Fibroma of Tendon Sheath
Usually located on tendon in palm or plantar surface Most commonly located on tendon of fingers
Cellular areas feature fascicles Cellular areas resemble nodular fasciitis


Knuckle Pads Fibroma of Tendon Sheath
Single nodule over any one joint Multinodular
Restricted to dorsal aspect of joints Located anywhere along tendon sheath


Benign Fibrous Histiocytoma Fibroma of Tendon Sheath
Rare in hands Common in hands
Histiocytes common Histiocytes rare
Giant cells common  Giant cells rare
Hemosiderin common  Hemosiderin rare
Smooth muscle actin may be scattered positive Smooth muscle actin strong positive


Cellular Fibroma of Tendon Sheath Adult or Infantile Fibrosarcoma
Common in hands Rare in hands in adults but may involve hands in infantile version
Rare >2 cm Frequently >4 cm
Cytologically bland Cytologically atypical
No atypical mitotic figures Atypical mitotic figures may be seen
Smooth muscle actin strongly positive Actin variable
Lacks t(12;15) t(12;15) present in most infantile cases


Cellular Fibroma of Tendon Sheath Synovial Sarcoma
Common in hands Rare in hands
Rare >2 cm Frequently >4 cm
Cytologically bland Cytologically atypical
No atypical mitotic figures Atypical mitotic figures may be seen
Smooth muscle actin strongly positive Actin negative
No SYT-SSX gene fusion SYT-SST gene fusion present


Fibroma of Tendon Sheath Calcifying Fibrous Pseudotumor
No calcification Calcification present
Inflammation uncommon Chronic inflammation present
Primarily located on digits Widely distributed
Slit-like vessels frequent Lacks slit-like vessels


  • Age range 1-77 years
    • Most common between 20-50
  • Most on wrist, hands, fingers
    • Remainder on forearms, toes and rare other sites
  • Slow growing
  • Rarely over 2 cm, never over 6 cm
  • May recur


Grading and Staging not applicable

The surgical pathology report should contain or address the following:

    • Location
    • Type of resection or biopsy
    • Histologic diagnosis
    • Managerial category Ib (Local recurrence do occur but are not destructive; never metastasizes)
    • Size
    • Depth (dermis, subcutis, below fascia, body cavity)
    • Margins
      • Involved
      • Not involved
        • If under 2 cm give all such distances and sites
        • If over 2 cm give minimum distance and site
    • Results of supplementary studies if performed
    • Relationship to other specimens from the same patient


Soft tissue "fibromas"


  • Kempson RL, Fletcher CDM, Evans HL, Henrickson MR, Sibley RS. Tumors of the Soft Tissues, Atlas of Tumor Pathology, AFIP Third Series, Fascicle 30, 2001
  • Fletcher CDM, Unni KK, Mertens F. Pathology and Genetics of Tumours of Soft Tissue and Bone, World Health Organization Classification of Tumours 2002
  • Weiss SW, Goldblum JR. Enzinger and Weiss's Soft Tissue Tumors, 4th edition, 2001
  • Dal Cin P, Sciot R, De Smet L, Van den Berghe H.  Translocation 2;11 in a fibroma of tendon sheath.  Histopathology 1998 May;32(5):433-5
  • Maluf HM, DeYoung BR, Swanson PE, Wick MR.  Fibroma and giant cell tumor of tendon sheath: a comparative histological and immunohistological study.  Mod Pathol 1995 Feb;8(2):155-9
  • Pulitzer DR, Martin PC, Reed RJ.  Fibroma of tendon sheath. A clinicopathologic study of 32 cases.  Am J Surg Pathol 1989 Jun;13(6):472-9
  • Humphreys S, McKee PH, Fletcher CD.  Fibroma of tendon sheath: a clinicopathologic study.  J Cutan Pathol 1986 Oct;13(5):331-8
  • Lundgren LG, Kindblom LG.  Fibroma of tendon sheath. A light and electron-microscopic study of 6 cases.  Acta Pathol Microbiol Immunol Scand [A] 1984 Nov;92(6):401-9
  • Hashimoto H, Tsuneyoshi M, Daimaru Y, Ushijima M, Enjoji M.  Fibroma of tendon sheath: a tumor of myofibroblasts. A clinicopathologic study of 18 cases.  Acta Pathol Jpn 1985 Sep;35(5):1099-107
  • Chung EB, Enzinger FM.  Fibroma of tendon sheath.  Cancer 1979 Nov;44(5):1945-54

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