An unusually large granular cell tumor of the pharynx: a case report and literature review.

We report a granular cell tumor of the pharynx in a 53 year-old woman who presented with a large retropharyngeal mass. Surgical excision revealed a 5.5 cm tan rubbery unencapsulated but circumscribed mass. Histologically, the tumor is composed of diffusely arranged oval and spindle cells with abundant eosinophilic granular cytoplasm and mildly pleomorphic nuclei without necrosis or mitoses. Immunostains show the tumor cells to be positive for S-100, vimentin, non-specific esterase and focally positive for inhibin. In addition to its unusual location, this tumor is extremely large while most granular cell tumors are small (<2 cm). This case represents a unique example of a large granular cell tumor at a rare location: the pharynx.