Granular cell ameloblastoma of jaw - Report of a case with an emphasis on its characterization.

Ameloblastoma is a neoplasm of odontogenic epithelium, especially of enamel organ-type tissue that has not undergone differentiation to the point of hard tissue formation. It accounts for approximately 10% of all tumors originating from gnathic bones. It exhibits diverse microscopic patterns which occurs either singly or in combination with other patterns. Granular cell ameloblastoma is a rare condition, accounting for 3.5% of all ameloblastoma cases that shows marked transformation in the cytoplasm of tumor cells, which are usually stellate reticulum like cells. The transformed cells possess very coarse, granular, eosinophilic cytoplasm. The "granular change" is thought to be due to a dysfunctional status of neoplastic cells, and the pathogenesis of this tumour seems to be age-related. Ultrastructural, histochemical, and immunohitochemical studies have revealed that cytoplasmic granularity is caused by overload; however the mechanism ivolved remains poorly understood. This article describes a case of granular cell variant of ameloblastoma affecting a 55-year old female. Key words:Ameloblastoma, granular cell, odontogenic tumor.