Small intestine & ampulla
Benign tumors / tumor-like conditions
Reactive nodular fibrous pseudotumor
Author: Hanni Gulwani, M.B.B.S.
Last author update: 1 August 2012
Last staff update: 19 April 2021
Copyright: 2003-2024, PathologyOutlines.com, Inc.
PubMed Search: Reactive nodular fibrous pseudotumor
Table of Contents
Definition / general | Gross description | Microscopic (histologic) description | Positive stains | Negative stains | Differential diagnosisCite this page: Gulwani H. Reactive nodular fibrous pseudotumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/smallbowelreactivenodular.html. Accessed April 16th, 2024.
Definition / general
- First described in 2003 in 5 patients (4 men), mean age 56 years (Am J Surg Pathol 2003;27:532)
- May present as obstruction (Am Surg 2011;77:790) but otherwise benign clinical course
Gross description
- Firm, tan white, 4 - 6 cm, solitary / multiple, in small bowel or colon
Microscopic (histologic) description
- Low / moderate cellularity
- Spindled fibroblasts arranged haphazardly or in intersecting fascicles
- Often infiltrative borders
- Stroma rich in wire-like, keloidal or hyalinized collagen
- Peripheral lymphoid aggregates
Positive stains
- Vimentin, CD117 or muscle specific actin (80%), smooth muscle actin or desmin (60%) (Int J Surg Pathol 2004;12:365)
Differential diagnosis
