BACKGROUND: Nature of granular cells in granular cell ameloblastoma (GCA) has always invoked considerable interest. The present study aims at antigenic characterization in five such cases with a panel of markers.
METHODS: Tissue specimens of five patients with GCA were fixed in buffered formalin and later embedded in paraffin wax. Blocks were sliced into 3 µ thick sections for immunohistochemical analysis using a panel of markers CD68, Bcl2, S100, p53, cytokeratin (AE1/AE3), vimentin and desmin.
RESULTS: All five cases were strongly positive for cytokeratin and CD68. S100 was negative in three cases and showed a mild positivity in two cases. Bcl2, p53, vimentin and desmin were negative in all the five cases.
CONCLUSIONS: This study presents a heterogenous nature of the granular cells; however, further validation is required with a larger sample size.

Ameloblastomas can present in various clinical and histomorphologic patterns. The granular cell variant accounts for only 3.5% to 5% of ameloblastomas. The aim of this case report is to present an example of ameloblastoma with unusual granular cell component, affecting a 63-year-old woman, in which both the inner and peripheral layers of follicles composed exclusively by eosinophilic granular cells. Assessment of the immunohistochemical and histochemical profile of the lesion was performed and the challenges of such a diagnosis were also addressed.

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.

Granular cell ameloblastoma (GCA) is one of the rare histological variants of ameloblastoma (1.5-3.5%), identified by Krompechner in 1918 and is diagnosed by the characteristic presence of granular cells. These granular cells are seen in several physiological and pathological conditions and the granularity in GCA is due to lysosomal aggregates. This review is about the clinical features, histopathological features and differential diagnosis of GCA and also adds the theories for occurrence of granularity, electron microscopic findings, cell signaling pathways and immunohistochemistry findings related to these granular cells in GCA.

An unusual granular variant of ameloblastoma presenting as a mandibular mass in a 43-year-old woman is described. These visually striking tumors display unusual and inconsistent immunohistochemical staining patterns although differential diagnosis from other granular cell lesions of the head and neck is usually not problematic.

Ameloblastoma is an epithelial odontogenic tumour of the jaw and exhibits diverse microscopic patterns which occurs either singly or in combination with other patterns. Peripheral ameloblastoma is a rare odontogenic soft tissue tumor, derived from epithelial and/or mesenchymal elements being part of the tooth-forming apparatus. The lesions responsible for approximately 1% to 5% of all cases of ameloblastoma affecting alveolar mucosa and gingiva occurring mainly, in the middle age. This article describes a case of peripheral ameloblastoma affecting a 35-year-old female. The lesion was located in the right buccal space. The occurrence and pathogenesis of peripheral ameloblastomas in general, are reviewed. The tumour was excised and no recurrence has been observed after twenty four months of surgery.