Unicystic Ameloblastoma with Pulse Granuloma: A Case Report and Literature Review with an Emphasis on Pathogenetic Mechanisms

Abstract

Innate immunity is essential for detecting and eliminating foreign substances, and oral pulse granuloma (OPG) is a rare reaction to vegetable or pulse material often seen in the oral cavity. This report presents a unique case where a dentigerous cyst transformed into unicystic ameloblastoma with concurrent OPG, offering insights into its development. A 15-year-old boy came to us with swelling in the right lower jaw. Clinical and X-ray findings pointed to an impacted wisdom tooth, and a dentigerous cyst was suspected. However, after surgical removal and closer examination under the microscope, the cyst was unexpectedly diagnosed as unicystic ameloblastoma containing unusual hyaline bodies. Further testing confirmed these as vegetable matter, leading to a diagnosis of OPG. The case displayed a rare “hyaline predominant” phase of OPG, fitting into stages of a foreign body reaction: material impaction, inflammation, giant cell response, and scarring. This case underscores the importance of detailed tissue analysis and special staining to identify OPG and differentiate it from other similar conditions. The findings highlight the rare coexistence of OPG with a cyst transforming into ameloblastoma, emphasizing the need for careful diagnosis to guide effective treatment.

Keywords

• foreign body
• giant cells
• granulomatous reactions
• odontogenic