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Table of Contents
Definition / general | Terminology | Epidemiology | Clinical features | Case reports | Treatment | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Cytology description | Cytology images | Positive stains | Negative stains | Electron microscopy description | Molecular / cytogenetics description | Differential diagnosis | Additional referencesCite this page: Shankar, V. Giant cell tumor of tendon sheath - diffuse type. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/softtissuegctdiffuse.html. Accessed February 16th, 2019.
Definition / general
- Extra-articular, destructive villonodular hyperplasia with synovial mononuclear cells mixed with multinucleated giant cells, foam cells, siderophages and inflammatory cells
- Considered the soft tissue counterpart of pigmented villonodular synovitis - may represent extension of articular tumor since often occurs near a joint
Terminology
- Also called tenosynovial giant cell tumor-diffuse type
- Called pigmented villonodular synovitis (PVNS) when occurs near a joint
- Note: terminology of giant cell tumors is inconsistent in literature
Epidemiology
- Rare; less frequent than localized type
- Usually < age 40 years, with female predominance
Clinical features
- Develops in synovial lining of joints, tendon sheaths and bursae
- Usually knee (80%); also ankle, hip, shoulder, elbow, foot
- Almost always monoarticular, painful swelling
- May actually be hyperplastic, 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 malignant)
Case reports
- 26 year old woman with tumor of subcutaneous thigh (Skeletal Radiol 2007;36:327)
- Arising in bursa of knee (Knee 2007;14:402)
Treatment
- Excision; may recur if inadequate excision; radiation therapy for recurrences
- See malignant for cases with malignant behavior
Gross description
- Brown-yellow spongy tissue, firm and nodular, often 5 cm or larger
Microscopic (histologic) description
- Diffuse expansive sheets of cells with infiltrative borders and variable cellularity; tumor margins are more cellular
- Also hyperplastic synovium with papillary projections composed of foamy histiocytes and hemosiderin containing macrophages
- Large clefts, pseudoglandular or alveolar spaces lined by synovial cells, osteoclast-like multinucleated (10 - 70 nuclei) giant cells, epithelioid cells
- Abundant collagen may be present, but lymphocytes and plasma cells are sparse
- Also giant hemosiderotic granules (2 - 3x diameter of RBC), giant siderophages (Pathologe 2005;26:96)
- May have 5+ mitotic figures / 10 HPF, rarely chondroid metaplasia (Mod Pathol 2007;20:545)
- Malignant if nodular and solid invasive growth plus large cells with large nuclei, prominent nucleoli, necrotic areas and atypical mitotic figures (see malignant)
Microscopic (histologic) images
Images hosted on other servers:
Shoulder tumor
Papillary tumor
Histiocytes and giant cells in dense connective tissue stroma
Iron deposits (Prussian blue stain)
Foam cells
Multiple synovial
lined clefts and
hemosiderin deposits
in the subsynovial layer
Multinucleated giant cells,
synovial cells, fibroblasts
and inflammatory cells
Cytology description
- Round, spindled and multinucleated cells without atypia
- Round cells have minimal cytoplasm and eccentric nuclei, occasional cytoplasmic hemosiderin, no mitotic figures
Cytology images
Images hosted on other servers:
Various images
Positive stains
- CD68 (stromal and giant cells, Hum Pathol 2003;34:65)
- Also CD31 (75%), calretinin (63%, Pathologe 2005;26:96), desmin (35 - 40%), CD14
- HAM56, CD45, and lysozyme (Arkh Patol 2010;72:34)
Negative stains
- S100 (but chondroid areas are S100+), CD45 / LCA, EMA, keratin, HMB45, CD34, smooth muscle actin
Electron microscopy description
- Features of histiocytes and fibroblasts (Ultrastruct Pathol 2002;26:15)
Molecular / cytogenetics description
- Clonal with neoplastic and reactive features
- Neoplastic due to CSF1 overexpression (Am J Surg Pathol 2007;31:970) or 1p13 (CSF1) rearrangements, often with COL6A3 at 2q35 (Proc Natl Acad Sci USA 2006;103:690)
- Also reactive features (Hum Pathol 2003;34:65)
- Translocations, t(2;3) and der(8) t(8;12) (Ultrastruct Pathol 2002;26:15)
- Some show trisomy of chromosome 5 & 7
Differential diagnosis
- Hemosiderotic synovitis: associated with hemophilia and intraarticular bleeding, no mononuclear or giant cell nodular proliferation, hemosiderin primarily in synovial lining cells
Additional references
