Warthin's Tumor: Electron Microscopic Studies

PAPILLARY cystadenoma lymphomatosum, a benign neoplasm of the human parotid gland, was first recognized in 1895 by Hildebrand1and was accurately described in 1910 by Albrecht and Arzt.2This tumor acquired its eponymic designation in 1929, when it was described in the American literature by Warthin.3 Warthin's tumor is thought to arise from salivary gland structures incorporated in lymph nodes adjacent to or embedded in the parotid gland.4,5Azzopardi and Hou4have demonstrated direct histological transition from normal ducts to tumor epithelium. Smith5considers Warthin's tumor to be the result of metaplastic and neoplastic alteration of salivary gland ductal epithelium accompanied by an increase in lymphoid tissue. In the light microscope, Warthin's tumor is seen to be made up of blunt, papillomatous processes, which consist of masses of lymphoid cells covered by a layer of pseudostratified epithelium.6These processes project into cystic spaces