EXPRESSION OF MATRIX METALLOPROTEINASE-9 IN ORAL SQUAMOUS CELL CARCINOMA AND ORAL PSEUDOEPITHELIOMATOUS HYPERPLASIA

Background: Oral pseudoepitheliomatous hyperplasia (PEH) appears histologically similar to oral squamous cell carcinoma (OSCC) in small oral biopsies, thus posing diagnostic dilemma. The objective of this study was to compare the expression of matrix metalloproteinase-9 (MMP-9) in differential diagnosis of OSSC and oral PEH. Materials & Methods: This comparative cross-sectional study was conducted in the Department of Histopathology, Armed Forces Institute of Pathology (AFIP), Rawalpindi, Pakistan from January 2013 to March 2016. It included sixty archival cases, 30 each of OSCC and PEH. Paraffin embedded blocks were prepared, hematoxylin and eosin stained sections taken and immunostained with MMP-9. The expression of MMP-9 was evaluated in OSCC and PEH. Results: The OSCC group included 16 (53.33%) men and 14 (46.67%) women, whereas PEH group included 18 (60%) men and 12 (40%) women. The mean age of OSCC group was 60.1 +/- 17.3 and that of PEH group was 52.7 +/- 16.6. In OSCC group, site of lesion was buccal mucosa in 12 (40%), gingiva 10 (33.33%), tongue 7 (23.33%) and floor of mouth 1 (3.34%) case. In PEH group, site of lesion was buccal mucosa in 12 (40%), tongue 11 (36.66%), gingiva 6 (20%) and palate 1 (3.34%) case. The expression of MMP-9 was positive in all the 30 cases of OSCC and negative in all 30 cases of PEH. Conclusion: Compared to pseudoepitheliomatous hyperplasia (PEH), MMP-9 revealed a higher expression in oral squamous cell carcinoma (OSCC). This finding has become mainstream strategy in distinguishing OSCC from PEH in oral mucosal biopsies in cases difficult to diagnose.