Squamous cells in fine-needle aspiration biopsies of salivary gland lesions: Potential pitfalls in cytologic diagnosis

A spectrum of neoplastic and non-neoplastic lesions of the salivary glands may contain squamous cells. These include chronic sialadenitis, lymphoepithelial cyst, pleomorphic adenoma, Warthin's tumor, mucoepidermoid carcinoma, and squamous cell carcinoma. The squamous cells may be a defining feature of the lesion, or an occasional and thus unexpected finding, with a consequent potential for misdiagnosis. Clinical management of these lesions differs significantly, and careful evaluation of the squamous elements, along with attention to other cellular and background components, facilitates accurate diagnosis.