An unusual presentation of dialysis-related amyloidosis: a large tumor extending from the gingiva to the palate.

Dialysis-related amyloidosis (DRA) is a clinically significant complication of long-term hemodialysis, primarily affecting the bones and joints. Involvement of oral cavity is uncommon, and almost all reported cases are localized to the tongue. Here, we report a rare case of DRA presenting as a large tumor originating from the maxillary gingiva in a hemodialysis patient. We also review previously reported cases of oral DRA. A 77-year-old Japanese woman with diabetic kidney disease had been receiving maintenance hemodialysis for 11 years. She was referred to our hospital for evaluation of a large tumor extending from the maxillary gingiva to the palate. Although she had been completely edentulous in the maxilla for years, she did not wear dentures. A biopsy specimen from the tumor revealed diffuse subepithelial deposition of eosinophilic, amorphous material, which was positive for direct fast scarlet stain and exhibited apple-green birefringence under polarized light. Immunohistochemistry confirmed the presence of β2-microglobulin, leading to the diagnosis of DRA. The tumor was surgically resected, and no recurrence was noted during follow-up. Our case and literature review suggest that chronic mechanical stimulation in the oral cavity may contribute to the development of oral DRA. These findings highlight the importance of regular oral examinations and the elimination of mechanical irritation in patients receiving maintenance hemodialysis.