Fibroblastic polyp of the colon / colonic perineuroma

Definition

A mesenchymal polyp of the colorectum comprising a monomorphic spindle cell proliferation separating entrapped colonic crypts. It is argued that fibroblastic polyp and perineuroma of the colon are the same entity5.

Epidemiology

Fibroblastic polyps constitute about 0.2% of all colonic polyps1. They are found across a wide adult age range.

Clinical features

Radiology

Macroscopic appearances

These polyps are up to 1.5 cm in diameter and solitary, but there are frequently associated hyperplastic polyps1.

Histopathology

The lesion is circumscribed but unencapsulated. The lamina propria is expanded by a monomorphic spindle cell proliferation. The spindle cells have pale cytoplasm and oval or tapered nuclei. The spindle cell proliferation widely separates colonic crypts. Cytological pleomorphism, necrosis and mitotic activity are absent.  Stellate and giant cells are not a feature. There is no necrosis. Mitotic figures are not seen. Mast cells are abundant. The overlying epithelium is intact.

 

Immunohistochemistry

   

Fibroblastic polyp

Perineuroma

 
 

Vimentin

14/141, 8/84

   

Fascin

4/43

 

CD34

2/141, 2/43

2/102

SMA

2/141, 0/84

0/102

S-100

0/141, 0/84

0/102

CD21

0/43

 

CD23

0/43

 

CD31

0/141

 

CD34

0/84

 

CD35

0/43

 

CD117

0/141, 0/84

0/102

EMA

0/141, 0/43, 0/84

9/102

AE1/AE3

0/84

 

MNF116

 

0/102

bcl-2

0/141

 

Desmin

0/141, 0/84

0/102

Caldesmon

0/84

0/102

Calponin

1/43

 

Claudin-1

 

4/102

GFAP

 

0/102

Neurofilament

 

0/102

Cyclin D1

0/43

 

PG-M1

0/84

 

CDX-2

0/84

 

Factor XIIIa

0/84

 

Ki-67

~1%4

 
     

Ultrastructure

The spindle cells are surrounded by collagen. They shows features of fibroblasts: sparse organelles, abundant intermediate filaments, a lack of basal lamina, dense bodies or pinocytotic vesicles.

Differential diagnosis

Prognosis

These tumours do not recur after resection.

References

1 Eslami-Varzaneh F, Washington K, Robert ME, et al. Benign fibroblastic polyps of the colon: a histologic, immunohistochemical, and ultrastructural study. Am J Surg Pathol 2004; 28:374-8

2 Hornick JL, Fletcher CD. Intestinal perineuriomas: clinicopathologic definition of a new anatomic subset in a series of 10 cases. Am J Surg Pathol 2005; 29:859-65

3 Zamecnik M, Chlumska A. Fibroblastic polyp of the colon shares features with Vanek tumor. Am J Surg Pathol 2004; 28:1397-8; author reply 1398.

4 Groisman GM, Polak-Charcon S, Appelman HD. Fibroblastic polyp of the colon: clinicopathological analysis of 10 cases with emphasis on its common association with serrated crypts. Histopathology 2006; 48:431-7

5 Groisman GM, Polak-Charcon S. Fibroblastic polyp of the colon and colonic perineurioma: 2 names for a single entity? Am J Surg Pathol 2008; 32:1088-94

 

This page last revised 20.7.2008

©SMUHT/PW Bishop