Mucous and Ciliated Cells in Oral Lesions: Potential Pitfall of Additional Two Cases

A 47-year-old Japanese male had a radicular cyst at the upper right first molar. Histologically, the lesion had a cystic wall comprising fibrous tissue lined by ordinary non-keratinized stratified squamous cells; however, the luminal surface was extensively replaced by columnar mucous cells and the superficial layer showed numerous cilia. A 16-year-old female had low-grade mucoepidermoid carcinoma at the base of the tongue. The tumor was 1.5 cm in size; presented a solid, relatively well-defined mass; histologically formed large and small nests adjacent to the minor salivary glands and skeletal muscle; and was accompanied by glandular cavities or cysts. A limited portion of the cystic structure had numerous cilia on the luminal surface. Mucous cells were immunoreactive for MUC1, MU4, and MUC5AC. Fluorescent in situ hybridization for MAML2 revealed obvious split signals. These two cases were added to discuss the diagnostic problems with mucous cells