Background and objectives: Pyogenic granuloma and peripheral giant cell granuloma are common focal reactive hyperplastic lesions affecting the gingiva. The aim of the present research was to study the clinical and histological features and the immunohistochemical expressions of Ki-67, Bcl-2, CD34, and α – SMA for gingival pyogenic granuloma in comparison with peripheral giant cell granuloma.
Methods: Formalin fixed, paraffin-embedded biopsy specimens of (48) gingival pyogenic granuloma and (39) peripheral giant cell granuloma, some of them retrieved from the archives of Duhok Central Public Lab, and the other from Rizgary Teaching Hospital, Erbil (Ministry of Health, Kurdistan region of Iraq) in the period between January/2010 and August /2015 were used in the study. Clinical and histological (Hematoxylin and eosin) features and immunohistochemical analysis for Ki-67, Bcl-2, CD 34(Micro vessel density) and α- SMA were studied in pyogenic granuloma and peripheral giant cell granuloma.
Results: The female to male ratio of pyogenic granuloma and peripheral giant cell granuloma was (1.18:1 and 1.43:1) respectively. The mean age was (32.47±19.575 and 35.03±18.22) year respectively. The pyogenic granulomas were mostly affecting the maxillary gingiva, while peripheral giant cell granulomas were mostly affecting the mandibular gingiva. Reactivity percentages for Ki-67 and Bcl-2 markers were significantly higher in peripheral giant cell granuloma compared to pyogenic granuloma (21.71±8.596% vs. 12.68±6.117 %, and 38.77±20.396% vs. 3.547±1.59%) respectively. The mean microvessel density in pyogenic granuloma was significantly higher than in peripheral giant cell granuloma (32.58± 17.778 vs. 22.4±11.208) respectively. The number of blood vessels with vascular surrounding cells non reactive to α-SMA in pyogenic granuloma was significantly lesser than that in peripheral giant cell granuloma ( 3.81±2.228 vs 10.53±3.432) respectively.
Conclusion: Pyogenic granuloma showed less proliferative and anti apoptotic activity compared with peripheral giant cell granuloma. In addition, more microvessel density and lesser number of blood vessels with vascular surrounding cells non reactive to α-SMA were seen. This can add insight to the clinical behavior and might reflect the differences in pathogenesis of these lesions.
Key words: Pyogenic granuloma, Peripheral giant cell granuloma, Ki-67, Bcl-2, CD 34