Fibroma of Tendon Sheath
Definition
- 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
