A case of a distinctive variety of basalαd squamous cell carcinoma (B8CC) of the floor of mouth is described Histologic evaluation of the tumor showed lobules and aggregates of medium-sized basaloid cells with distinctive periph eral palisading and focal areas of comedo- necrosis. This appearance together with microcystic spaces simulated that of an adenoid cystic carcinoma. Accompanying epithelial dysplasia of the overlying mucosa was found. Immunohistochemistry of the tumor revealed diffuse strong expression for cytokeratin AE1/3, focally positive for Epithelial Membrane Antigen in the inner cells of tubular structures However, CEA, 8-100, smooth muscle actin, and vimentin were negative. The histologic differential diagnosis considered were adenoid cystic carcinoma and adenosquamous cell carcinoma Immunohistochemistry and awareness of this unusual pattern of B8CC will facilitate the correct diagnosis being reached.

• 윤정훈(조선대학교 치과대학 병리학교실) | Jung Hoon Yoon Correspondence
• 안상건(조선대학교 치과대학 병리학교실) | Sang Gun Ahn Correspondence