Oral vegetable granuloma: ultrastructural and histological study.

An unusual giant-cell granulomatous inflammatory oral lesion is characterised by the presence of hyaline rings and by a lack of agreement on their nature, opinions ranging from their being hyaline degenerative blood-vessels to remains of leguminous cells. Ten such lesions and a variety of vegetables have been examined in the present investigation. Light-microscopical examination of the lesions revealed the hyaline rings surrounded by inflamed granulation tissue with associated multinuclear giant cells. Electron-microscopical examination showed them to consist of a material similar to that of vegetable cell walls, sometimes with an associated superficial layer of collagen. The observations indicate that the lesions consist of vegetable remains with an associated foreign-body type of inflammatory response.