Abstract
Warthin tumor is a benign salivary gland tumor comprising ductal epithelium and lymphoid stroma. To date, reports about the malignant transformations of intraepithelial and lymphoid components in Warthin tumor are extremely rare; lymphoid malignant transformation into B-cell lymphoma is particularly rare in combination with T-cell lymphoma. The case of Warthin tumor complicated with T-lymphoblastic lymphoma is reported to emphasize the importance of a careful light microscopic evaluation of lymphoid tissue in Warthin tumor for identifying occult lymphoma presence, reducing misdiagnosis and missed diagnosis, and determining a timely treatment.