Oral cavity
Other benign tumors / conditions
Solitary fibrous tumor

Reviewer: Nat Pernick, M.D. (see Authors page)

Revised: 29 September 2015, last major update November 2013

Copyright: (c) 2002-2015, PathologyOutlines.com, Inc.

PubMed Search: solitary fibrous tumor[title] oral
  • Rare, < 50 cases reported; mean age 56 years
  • Slow growing, asymptomatic, submucosal tumor
  • Benign; no recurrence or metastases reported (similar behavior to other sites)
  • No associated systemic manifestations reported with oral cavity tumors
  • Sites: usually buccal mucosa, also tongue and lower lip; more likely on left side of mouth
  • References: Am J Surg Pathol 2001;25:900
Gross Description
  • 1-4 cm, well circumscribed, round / oval, smooth surface
Micro Description
  • Well circumscribed tumor composed of hypercellular and hypocellular collagenous zones with haphazardly arranged, bland spindle and ovoid cells between thin and thick collagen fibers
  • Prominent hemangiopericytoma-like vascular pattern, perivascular hyalinization
  • Variable myxoid stromal change, focal fascicular or storiform patterns of spindle cells, smooth muscle-like cells with blunt ended nuclei, epithelioid cells, mitotic activity (up to 2 per 10 HPF), stromal multinucleated giant cells and mast cells
  • Occasional encapsulation, nuclear pseudoinclusions; no atypical mitotic figures, no necrosis
Micro Images

    Contributed by Dr. Bushra Sikandar, The Dow University of Health and Sciences (Pakistan):




Positive Stains
  • CD34, bcl2, vimentin, Factor XIIIa (focal) and CD99 (75%)
Negative Stains
  • S100, cytokeratin, CD68, desmin and muscle specific actin
Differential Diagnosis
  • Benign fibrous histiocytoma: CD34-, bcl2-
  • Hemangiopericytoma: may be CD34-, controversial whether it is a distinct entity
  • Myofibroma / fibroma: smooth muscle actin+, muscle specific actin+, CD34- in myofibroma
  • Neurofibroma or schwannoma: S100+, CD34-
  • Spindle cell lipoma: usually prominent fat, lack of prominent vasculature)