The central granular cell odontogenic tumor is a rare benign odontogenic neoplasm of uncertain hisotogenesis characterized by varying amounts of eosinophilic granular cells and apparently inactive odontogenic epithelium with variable presence of calcified tissue. We present a case of central granular cell odontogenic tumor involving the maxilla of 35-year-old man with immunohistochemical characterization of granular cells. In microscopic view, the granular cells densely packed in sheets and lobules with abundant eosinophilic, granular cytoplasm and eccentric round-to-ovoid nuclei revealed immunoreactivity for vimentin, α1-antitrysin and CD68, and NSE but not for cytokeratin and S-100 protein while the interspersed odontogenic epithelial cells were positive for cytokeratin only. Granular cells also revealed strong PAS staining. Numerous concentric structured round to ovoid calcified aggregates were also noted. The lesion was treated with excision without recurrence for 8 years. Our immuohistochemical staining findings also suggest that the granular cells of central granular cell odontogenic tumor are mesenchymal in origin with possible histiocytic differentiation

Central granular cell odontogenic tumor (CGCOT) is a rare benign odontogenic neoplasm, with approximately 30 cases having been reported. The pathogenesis of CGCOT as well as the designation of this lesion is controversial because of unknown histogenesis of the granular cell. We present an additional case of CGCOT involving the mandible of a 50-year-old Korean man who complained of asymptomatic swelling of the right buccal gingiva. Current lesion is microscopically characterized by densely packed polyhedral granular cells surrounding interspersed islands or strands of odontogenic epithelium. Immunohistochemically, granular cells were positive for Vimentin and CD68, and negative for cytokeratin and S-100. These features support a mesenchymal origin for the granular cells as other results previously reported.