Oral pyogenic granuloma: Various concepts of etiopathogenesis

Abstract

Pyogenic granuloma or granuloma pyogenicum is a well-known oral lesion. The name pyogenic granuloma is a misnomer since the condition is not associated with pus and does not represent a granuloma histologically. Pyogenic granuloma of the oral cavity is known to involve the gingiva commonly. Extragingivally, it can occur on the lips, tongue, buccal mucosa, palate, and the like. A history of trauma is common in such sites. The etiology of the lesion is not known, though it was originally believed to be a botryomycotic infection. It is theorized that pyogenic granuloma possibly originates as a response of tissues to minor trauma and/or chronic irritation, thus opening a pathway for invasion of nonspecific microorganisms, although microorganisms are seldom demonstrated within the lesion. Pathogenesis of pyogenic granuloma is still debatable. Medline and PubMed databases were searched under the following key terms: Pathogenesis of oral pyogenic granuloma, pyogenic granuloma, and oral pyogenic granuloma. This search was limited to articles on human/animal studies which were published in English language. After reviewing the searched articles, the relevant articles were selected for the present review. Through this article, we have tried to summarize and present all the concepts of pathogenesis related to this most common and most mysterious oral lesion.

Pyogenic Granuloma of Gingiva: A Misnomer

“…Hullihen in 1844, reported the first case in literature. In 1897, occurance of PG in man was first described as Botryomycosis hominis by Poneet and Dor [1,3]. The term Pyogenic granuloma or Granuloma pyogenicum was coined by Hartzell in 1904 [3].…”

“…Kerr and Bhaskar et al observed various Gram +ve and Gram-ve bacilli more commonly in ulcerated lesions near the surface tan in deeper aspects suggesting contamination from oral flora. Shafer et al stated that some minor trauma to tissue provided pathway for invasion of non-specific types of microorganisms [1,3]. The tissue responds to these low virulence organisms by overzealous proliferation of a vascular type of connective tissue.…”

“…Various etiological agents have been suggested to initiate PG, like chronic low grade irritation due to exfoliation of primary tooth, eruption of permanent teeth, defective or overhanging restoration, food impaction or tooth brush trauma, sharp tooth [1,3,4]. Other factors such as hormones, drugs, gingival inflammation and preexisting vascular lesions lead to the development of these lesions.…”

“…Growth over the gingival tissues may be focal or generalized, often the result of an underlying systemic disease, drug-induced or local iatrogenic factors [1].The localized reactive hyperplastic lesions (LRHL) are often a diagnostic dilemma as they manifest clinically in a similar manner [1]. LRHL of gingiva are categorized into four sub-types like Focal Fibrous Hyperplasia (FFH), Pyogenic Granuloma (PG), Peripheral Ossifying Fibroma (POF) and Peripheral Giant Cell Granuloma (PGCG) [2].…”

“…They described PG in 2 forms as lobular capillary hemangioma (LCH) and Non-LCH. The various other terminologies used were granuloma Pediculatum Benignum, Benign vascular tumor and during pregnancy as Granuloma gravidarum [1,3].…”