Xanthogranulomatous Sialadenitis, an Uncommon Reactive Change is Often Associated with Warthin's Tumor

Xanthogranulomatous sialadenitis (XGS) is rare in salivary glands and only reported in the literature as single cases. Here we report a cohort of four cases with XGS and summarize the clinicopathologic features of these cases. All four patients had persistent mass lesions concerning for neoplasm. In two patients (patient 1 and 3), the initial fine needle aspirations (FNAs) contained oncocytic cells consistent with or suspicious for Warthin's tumor, but follow-up FNAs showed only inflammation and/or debris indicating tumor infarction after FNA. All patients eventually had surgical resection. Histologically, all cases contained abundant macrophages with necrosis and fibroblastic proliferation. Warthin's tumor with a grossly identifiable tumor nodule (0.7 cm) was noted in patient 1 and a microscopic focus (0.2 cm) of Warthin's tumor was identified in patient 3. No identifiable tumor was observed in patient 2 and 4. There are a total of 10 XGS cases in the literature (including four from this series) and Warthin tumor was identified in 50% of reported cases of XGS, suggesting that XGS is an uncommon reactive process to spontaneous or procedure-induced infarction of Warthin tumor. As a diagnostic mimicker for malignancy, a thorough examination and generous sampling of surgical resection specimen is warranted, although a benign salivary gland neoplasm, commonly Warthin's tumor, is often identified.