Table of ContentsDefinition / general | Essential features | Terminology | ICD coding | Sites | Clinical features | Prognostic factors | Case reports | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Molecular / cytogenetics description | Differential diagnosis | Board review question #1 | Board review answer #1
Cite this page: Gonzalez R. Solitary fibrous tumor. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/colontumorSFT.html. Accessed May 23rd, 2019.
Definition / general
- Mesenchymal tumor that can very rarely involve the gastrointestinal tract
- Mesenchymal lesion of variable malignant potential
- Positive for CD34 and STAT6
- Formerly also called "hemangiopericytoma"
- Usually presents as a pelvic / retroperitoneal mass but may rarely arise as a colon polyp
- Atypical features can predict recurrence / metastasis (see Microscopic (histologic) description)
- Firm, solid lesion
Microscopic (histologic) description
- Spindle cells arranged in a "patternless pattern" with collagenous background
- Staghorn vessels throughout, particularly at periphery
- Atypical / malignant features include increased cellularity, nuclear atypia, mitotic activity and necrosis (Am J Surg Pathol 1998;22:1501)
Microscopic (histologic) images
Molecular / cytogenetics description
- NAB2-STAT6 gene fusion (not demonstrated in colon case reports but likely present)
Board review question #1
Which of the following immunohistochemical stains can reliably distinguish gastrointestinal stromal tumor from solitary fibrous tumor?
Board review answer #1
D. STAT6 (Arch Pathol Lab Med 2002;126:1189)