Stromal myofibroblasts in focal reactive overgrowths of the gingiva

Leonardo Silveira Damasceno,Paulo Eduardo Alencar Souza,Martinho Campolina Rebello Horta,Fernanda Da Silva Gonçalves,Elton Gonçalves Zenóbio,Edson Costa E Silva

doi:10.1590/s1806-83242012005000012

Abstract

Focal reactive overgrowths are among the most common oral mucosal lesions. The gingiva is a significant site affected by these lesions, when triggered by chronic inflammation in response to microorganisms in dental plaque. Myofibroblasts are differentiated fibroblasts that actively participate in diseases characterized by tissue fibrosis. The objective of this study was to evaluate the presence of stromal myofibroblasts in the main focal reactive overgrowths of the gingiva: focal fibrous hyperplasia (FFH), peripheral ossifying fibroma (POF), pyogenic granuloma (PG), and peripheral giant cell granuloma (PGCG). A total of 10 FFHs, 10 POFs, 10 PGs, and 10 PGCGs from archival specimens were evaluated. Samples of gingival mucosa were used as negative controls for stromal myofibroblasts. Oral squamous cell carcinoma samples, in which stromal myofibroblasts have been previously detected, were used as positive controls. Myofibroblasts were identified by immunohistochemical detection of alpha smooth muscle actin (α-sma). Myofibroblast immunostaining was qualitatively classified as negative, scanty, or dense. Differences in the presence of myofibroblasts among FFH, POF, PG, and PGCG were analyzed using the Kruskal-Wallis test. Stromal myofibroblasts were not detected in FFH, POF, PG, or PGCG. Consequently, no differences were observed in the presence of myofibroblasts among FFH, POF, PG, or PGCG (p > 0.05). In conclusion, stromal myofibroblasts were not detected in the focal reactive overgrowths of the gingiva that were evaluated, suggesting that these cells do not play a significant role in their pathogenesis.

Highlights

Focal reactive overgrowths are among the most common lesions of the oral mucosa.[1]
Immunohistochemistry Myofibroblasts were identified by the immunohistochemical detection of alpha smooth muscle actin (α-sma), a marker for myofibroblasts
No stromal myofibroblasts were observed in focal fibrous hyperplasia (FFH) (Figure 1A), peripheral ossifying fibroma (POF) (Figure 1B), pyogenic granuloma (PG) (Figure 1C), or peripheral giant cell granuloma (PGCG) (Figure 1D)

Summary

Introduction

Focal reactive overgrowths are among the most common lesions of the oral mucosa.[1]. The gingiva is an important area affected by these lesions,[1,2] primarily triggered by chronic inflammation in response to microorganisms in dental plaque.[2,3,4,5,6,7] These lesions are composed of one or more of the following connective tissue components: collagen, bone, endothelial cells, and multinucleated giant cells.[1,2,7]The most common focal reactive overgrowths of the gingival connective tissue are: focal fibrous hyperplasia (FFH), peripheral ossifying fibroma (POF), pyogenic granuloma (PG), and peripheral giant cell granuloma (PGCG).[4,7,8]FFH, known as irritation fibroma, is a focal reactive hyperplasia of fibroblasts with overproduction of collagen.[2,5,7] POF is a focal reactive hyperplasia of fibrous connective tissue presenting bone formation.[7,9] PG is a focal reactive growth of granulation tissue with marked proliferation of endothelial cells and blood vessel formation.[5,7] PGCG is a focal overgrowth composed of mononuclear and multinucleated giant cells.[3,6,7]. FFH, known as irritation fibroma, is a focal reactive hyperplasia of fibroblasts with overproduction of collagen.[2,5,7] POF is a focal reactive hyperplasia of fibrous connective tissue presenting bone formation.[7,9] PG is a focal reactive growth of granulation tissue with marked proliferation of endothelial cells and blood vessel formation.[5,7] PGCG is a focal overgrowth composed of mononuclear and multinucleated giant cells.[3,6,7]

Objectives

Methods

Conclusion