2.Department of Pathology, Hadassah Hebrew- University Medical Center, Jerusalem, Israel.
Background: Warthin tumor is a common benign salivary gland lesion. Its optimal treatment mode is controversial. We analyze the accuracy of Warthin tumor pre-operative fine-needle aspiration (FNA)-based diagnosis and reassess the treatment paradigm. The risk of missing malignant tumors, falsely demonstrating a cytological benign Warthin tumor in the pre-operative FNA, is to be explored.
Methods: Retrospective cohort study in a tertiary university hospital. Data on all parotidectomy cases between 1996 and 2010 (n=238) was analyzed. Cytological accuracy was calculated in 2 different opposing ways. First, we considered cases with a correct pre-operative identification of histologically proven Warthin tumors as true positives. The second assessment was done by gathering all cytological examinations suggesting a Warthin tumor, which were later excised. The histological identification of a malignant tumor was considered as a false negative.
Results: FNA was found to be accurate in 48 out of the 61 patients who had a final pathologic diagnosis of Warthin tumor, i.e. a 78.7% sensitivity. In the second step, there were 50 FNA's suggesting a Warthin tumor, One case turned out to be malignant: a low-grade muco-epidermoid carcinoma. The negative predictive value was therefore 98%.
Conclusions: The overall accuracy of FNA suggesting Warthin tumor in a tertiary university hospital is high. We offer, in selected patients, observation as a reasonable alternative treatment to surgery. However, we also advise a repeat ultrasound-guided FNA to confirm the initial diagnosis.