A case of acinic cell carcinoma arising in the lower lip

We present a case of acinic cell carcinoma with a papillary-cystic pattern arising in the lower lip of a 62-year-old female. Histopathologically, the tumor had numerous, variably sized cystic structures, which grew in a papillary fashion toward the cystic lumen with a single-layer of lining epithelium. Furthermore, the tumor cells showed ‘hobnail’ and ‘tombstone row’ appearances. Histochemically, a few tumor cells were positive for PAS and were diastase resistant but mucicarmine staining was negative. Immunohistochemically, the tumor cells were positive for S-100 protein, and a few tumor cells were positive for amylase. Therefore, this case was diagnosed as acinic cell carcinoma with a papillary-cystic pattern.