Xanthomatous sialadenitis: Autoimmune- or treatment-induced lesions?

Xanthomatous sialadenitis (XS) is rarely reported. Here we report XS in a case of HLA-B27-positive ankylosing spondylitis showing also anti-MAG-positive polyneuropathy with IgM-kappa dysimmunoglobulinemia/paraproteinemia, lung small cell carcinoma and buccal squamous cell carcinoma (SCC). The lesions were identified in submandibular and labial minor salivary glands of a neck dissection specimen (made during a buccal 1.7 cm large SCC resection procedure). The oral SCC was resected at 8 months after the diagnosis of the lung small cell carcinoma (with skull dome metastases, revealed by a superior cava syndrome) and at 2 months after radiotherapy. The microscopic XS-lesions consisted in multifocal accumulations of CD68-positive macrophages. Plasmocyte-abundant foci (CD138-positive) were extra-xanthomatous (atrophic parenchyma, zones of adipose involution). CD138 was also expressed in ductal cells and in acini (focally). In conclusion, we report XS of submandibular and labial minor salivary glands, occurring in the context of a HLA-B27-positive ankylosing spondylitis, polyneuropathy with IgM-kappa dysimmunoglobulinemia and anti-MAG antibodies in a case of small cell lung carcinoma (treated by radio-chemotherapy) and oral SCC.