Primary Necrobiotic Xanthogranulomatous Sialadenitis with Submandibular Gland Localization without Skin Involvement

Xanthogranulomatous change in a pleomorphic adenoma: An extremely rare variant/degenerative change. Is it fine needle aspiration induced?

Pleomorphic adenoma (PA) is the most common benign salivary gland tumor characterized by morphological diversity, metaplastic changes, degeneration, cystic change, altered differentiation, and rarely malignant transformation, thereby may create a diagnostic dilemma on cytology. Xanthogranulomatous (XG) inflammation within a PA could be due to XG sialadenitis coexistent with PA or preoperative fine-needle aspiration cytology (FNAC) induced histologic alteration. The argument in favor of this hypothesis is that the changes seen in the histopathology would not be present in the cytology, implying that the alterations were most likely due to the traumatic injury of needling rather than spontaneous change of the lesions themselves. These FNAC induced changes are focal in most of the cases, so the underlying lesion is readily identifiable, but on rare occasions they are so extensive that it can masquerade as a malignancy. We report a case of XG change in a PA in a 39-year-old male of 8 years standing. Through this case we wish to emphasize that knowledge of a previous FNAC and its potential effects on histology of the subsequent surgical specimen is necessary to avoid potential misdiagnosis.

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.