Basaloid monomorphic adenoma presenting as an expanding buccal mass: a case report

Basal cell adenoma-an unusual presentation

Basal cell adenoma is an uncommon epithelial neoplasm of the salivary gland most commonly arising in the parotid glands. We report a case of basal cell adenoma of the minor salivary gland presenting as a slowly progressing, large parapharyngeal mass. Histopathology revealed a well-encapsulated mass with characteristic histomorphology. Immunohistochemistry showed selective positivity for pancytokeratin, S-100, and smooth muscle actin in the tumor which highlighted the participation of myoepithelial cells in histogenesis. In addition, positivity was noted for carcinoembryonic antigen and vimentin. Ultrastructural analysis showed characteristic features including reduplicated basal laminae around the tumor cells, presence of intermediary filaments, and rough endoplasmic reticulum in the cytoplasm. There are no reports of basal cell adenoma presenting as a parapharyngeal mass lesion in the available English literature. This case highlights the rarity of this tumor with regard to its site of origin, possibly from a minor salivary gland.