Joint tumors
Fibrous histiocytoma of tendon sheath

Topic Completed: 1 June 2013

Revised: 8 March 2019

Copyright: 2002-2019,, Inc.

PubMed Search: Fibrous histiocytoma of tendon sheath "loattrfree full text"[sb]
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Cite this page: Shankar V Fibrous histiocytoma of tendon sheath. website. Accessed April 19th, 2019.
Definition / general
  • Also called tenosynovial giant cell tumor, giant cell tumor of tendon sheath, nodular tenosynovitis, xanthogranuloma, benign synovioma
  • Ages 20s - 40s, usually women
  • Develops in synovial lining of joints, tendon sheaths and bursae
  • Usually knee (80%); also ankle, hip, shoulder or elbow joint and foot
  • Almost always monoarticular, painful swelling
  • May actually be hyperplastic / reactive, not neoplastic (Hum Pathol 2003;34:65)
  • Occasionally invades underlying bone; may cause bone cyst formation, loss of bone and cartilage
  • Locally aggressive; often recurs but only rarely has malignant behavior (see below)
  • 15% erode adjacent bone by pressure
  • May be related to Tendon sheath fibroma
Clinical features
  • Malignant variant:
    • Mean 61 years, no gender preference
    • Usually extra-articular, near large joints or extremities
    • Most common location is knee joint
    • High number of mitotic figures, marked nuclear hyperchromasia, few multinucleated giant cells
  • Case reports
    • Excision (benign) but may recur locally
    Clinical images

    Images hosted on other servers:


    Palmar aspect of middle phalanx of index finger

    Firm, nodular, nontender thumb mass

    Dome shaped nodule (Fig. 1)

    Well demarcated yellowish lobulated tumor (Fig. 3)

    Gross description
    • Discrete encapsulated nodule, 1 - 3 cm on tendon sheath, may be attached to synovium by a pedicle
    • Red brown to orange yellow, localized, well circumscribed, resembles small walnut; diffuse form may be larger and infiltrative
    Gross images

    Images hosted on other servers:

    Excised giant cell tumor

    Microscopic (histologic) description
    • Polymorphic infiltrate of small histiocytes, multinucleated giant cells within dense fibrous tissue with hemosiderin and foamy macrophages
    • Mitotic figures and focal hyalinized areas; tumor margins are more cellular
    Microscopic (histologic) images

    Images hosted on other servers:

    2A: H&E with multinucleated giant cells and
    mononuclear cells; B: mononuclear cells are HAM56+;
    C: giant cells and some mononuclear cells are TRAP+; 3:
    differentiation sequence of giant cell tumor

    Giant cell (Case presentation: Fig. 2)

    Low power and high power

    Circumscribed lobulated nodule (Fig. 4)

    Histiocytes with
    abundant eosinophilic
    cytoplasm (Fig. 5)

    Low power view of thumb tumor

    High power view of cellular zone

    High power view of hypocellular zone

    CD68 immunostaining of cellular zone

    Ki67 immunostaining of peripheral zone

    CD45 immunostaining of peripheral zone

    Electron microscopy description
    • Synovial cells, fibroblasts, histiocytes, lymphocytes
    Differential diagnosis
    • Epithelioid sarcoma: granulomalike formations, necrosis, invasive, epithelioid features, keratin+
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