Granular Cell Transformation in Plexiform Ameloblastoma: Case Report and Literature Review

Abstract

Ameloblastoma is the most common odontogenic tumor, primarily occurring in the posterior mandible. It is a slow-growing yet locally invasive epithelial tumor that generally follows a benign course. Granular cell ameloblastoma is a rare variant differentiated by the nests of large eosinophilic granular cells resulting from cytoplasmic transformation. This variant is considered to be more aggressive than any other variant. We report a rare case of plexiform ameloblastoma with granular cell transformation in a 50-year-old male patient presenting as a painless swelling on the right side of the body of the mandible. While granular cell ameloblastoma transformation is well documented in follicular ameloblastoma, its presence in the plexiform variant is extremely rare. This case expands the histologic spectrum of ameloblastoma and underscores the importance of recognizing such variations to avoid diagnostic confusion. Additionally, we re-evaluate the widely held belief regarding its aggressiveness, highlighting emerging evidence that challenges its traditionally aggressive nature. The patient underwent surgical excision in December 2024 and remains under early postoperative follow-up, with long-term monitoring planned to assess recurrence and progression.