Reactive localised inflammatory hyperplasia of the oral mucosa

Objective: To document the histopathological pattern and distribution of reactive localised inflammatory hyperplastic lesions of the oral mucosa diagnosed at the university of nairobi dental hospital over a 14 year period. Design: A retrospective, cross-sectional descriptive study. Setting: Division of oral pathology and oral medicine, histopathology laboratory, school of dental sciences, university of nairobi. Subjects: A total of 3135 oral biopsies were accessioned in the oral diagnostic histopathological laboratory registry over a period of 14 years from march 1991 to december 2005. Results: Three hundred and thirty three cases were histopathologically diagnosed as reactive inflammatory hyperplasias of the oral mucosa. This constituted 10.6% of the total oral biopsy specimens analysed during this period. Fibrous epulis was the most common histological sub-type with 129 cases (38.7%) followed by pyogenic granuloma with 94 (28.3%) cases. Six (1.8%) caseswere peripheral giant cell granuloma and three cases(0.9%) were those of denture irritation hyperplasia. The age distribution ranged from 2 to 78 years( mean=30.5 years) with a peak at 20-29 years. Gender distribution showed that 107 (32%) cases occurred in males and 226 (68%) cases females. Similar trends were observed in most of the histological sub-types. Fibrous epulis occurred in 41 male (31.8%) cases and in 88 (68.2%) females with an age range of 2 to 78 years ( mean = 30.5 years). As for the pyogenic granuloma, 26 (27.7%) lesions occurred in males and 68 ( 72.3%) in females with an age range of 2 to 75 years ( mean = 30.1 years). Among all the histopathological sub-types it was shown that 223 (67.0%) cases were fibrous, 104 (31.2%) vascular and six (1.8%) peripheral giant cell granuloma. Gingival lesions were the most common with 257 (77.2%) cases followed by 28 (8.4%) in the tongue, 16(4.8%) lips, 15 (4.5%) cheek, six (1.8%) palate and the rest on the floor of the mouth and other mucosal sites. The duration of these lesions was recorded in 182 (54.7%) cases and ranged from 1 week to 16 years (mean=1.8 years).only 15 (4.5%) cases were reported to have recurred and all of them were gingival lesions. Conclusion: The present study has shown that the prevalence of reactive localised inflamatory hyperplasia (rlihs) of the oral mucosa was 10.6% with fibrous epulis and pyogenic granuloma having been the most common histopathological sub-types predominantly affecting females. Although rlihs are distinguished on clinical or histopatholocal grounds, it is important to appreciate that they are variations of the same basic process.