The ameloblastoma is a slowly growing, locally invasive, benign epithelial odontogenic neoplasm of the jaws with a high rate of recurrence if not removed adequately. We report an interesting case of granular cell ameloblastoma, which presented as a solitary, peripheral, soft tissue growth 20 years after initial segmental resection of the left mandible. The basal layer of oral mucosa could be the possible source of peripheral ameloblastoma in our case. In order to reduce the chances of recurrence, we suggest to incorporate mucosal stripping along with the conventional treatment as a mandatory rather than an elective procedure while treating ameloblastoma.

Granular cell ameloblastoma is classified as a histological subtype of solid/multicystic ameloblastoma. Usual granular cell ameloblastoma is histologically characterized by granular changes of stellate-like cells located in the inner portion of the epithelial follicles. Here we report a case of another type of granular cell ameloblastoma, showing predominant anastomosing double-stranded trabeculae of granular cells. This type of granular cell ameloblastoma is extremely rare, and the World Health Organization classification does not contain the entity. We tentatively termed it \'anastomosing granular cell ameloblastoma\' in this report. The present case suggests the importance of differential diagnosis because the histology of \'anastomosing granular cell ameloblastoma\' resembles that of salivary gland oncocytoma rather than that of usual granular cell ameloblastoma. The trabeculae observed in our case continued to the peripheral cells of a small amount of epithelial sheets of plexiform ameloblastoma, and the tumor cells were positive for CK19, which is regarded as an immunohistochemical marker of odontogenic epithelium. Similar to usual granular cell ameloblastoma, the tumor cells had CD68-positive granules. For precise diagnosis of this condition, immunohistochemistry using CK19 and CD68, as well as detailed histological observation, are recommended.