Benign tumors
Solitary fibrous tumor

Author: Monika Roychowdhury, M.D. (see Authors page)

Revised: 22 June 2016, last major update December 2014

Copyright: (c) 2003-2016,, Inc.

PubMed Search: Bladder [title] Solitary fibrous tumor
Cite this page: Solitary fibrous tumor. website. Accessed October 23rd, 2016.
Definition / General
  • Rare tumor in bladder, similar to counterparts elsewhere
  • Men ages 50-67 years
  • < 50 cases reported
Clinical Features
  • Often misdiagnosed (Hum Pathol 2000;31:63)
  • Benign behavior (usually)
  • Slow growing, painless, well-delineated mass, may lead to compression symptoms
  • Rarely causes paraneoplastic syndrome (hypoglycemia secondary to insulin-like growth factor, known as Doege-Potter Syndrome)
Prognostic Factors
  • Unpredictable behavior
  • Malignant transformation and large size associated with poor outcome
  • Atypical cytologic features, increased mitotic activity (>4/10hpf), size >10cm and resectability are important prognostic factors to predict recurrence or metastatic behavior
Case Reports
  • Excision, usually do not recur but follow up recommended
Gross Description
  • Often very large, well-circumscribed, tan-colored mass which often has a pedicle
Gross Images

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Well circumscribed tumors

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Solid, tan, fibrotic tumor

Micro Description
  • Resembles pleural counterpart: haphazard (patternless) spindle cells with hypo- and hypercellular areas, and deposition of dense collagen
  • Spindly to oval epithelioid cells form short fascicles or clusters
  • May have hemangiopericytoma-like vascular pattern
  • Generally scarce mitoses - usually less than 3 mitoses per 10 high power fields
Micro Images

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Plump spindled cells with prominent vasculature

Differential Diagnosis
  • Sarcoma
  • Sarcomatoid carcinoma