Basaloid squamous carcinoma simulating adenoid cystic carcinoma: Diagnostic dilemma

SummaryThe adenoid pattern seen in Basaloid squamous carcinoma (BSC) and adenoid cystic carcinoma (ACC) of head neck region may form a major portion in biopsies and pose diagnostic difficulties. In the present case histology of tongue swelling revealed an adenoid pattern with squamous differentiation and keratin pearls in some of these adenoid spaces. The overlying mucosa showed an in situ squamous carcinoma. Immunohistochemical (IHC) stains showed CK and EMA positivity in squamous and adenoid areas, CEA was positive only in squamous areas while Vimentin and S100 protein were negative. These IHC stains thus helped in the distinction of BSC from ACC as ACC is clinically less aggressive.