Introduction: Localized amyloidosis in the head and neck is a rare and generally benign condition. In the oral cavity, amyloidosis usually involves the tongue or buccal mucosa. We present the second case of oral amyloidosis arising in the gingiva ever reported, to the best of our knowledge.
Case presentation: A 73-year-old White Spanish man presented a persistent nodular mass involving his upper gingiva. The lesion was surgically resected and the histological examination revealed a subepithelial, multinodular amorphous and fibrillar accumulation. Staining of the specimen for Congo red proved positive, exhibiting a reddish colour under light microscopy and apple-green birefringence under polarized light. With immunohistochemical tests, pentagonal amyloid component was demonstrated. An extensive study excluded any systemic involvement; a diagnosis of localized primary amyloidosis was made. After 2 years of follow-up, no clinical progression to systemic amyloidosis or local recurrence was observed.
Conclusions: Localized amyloidosis of the gingiva is an extremely rare condition that seems to show no clinically distinct feature. Histologic examination is the first step towards diagnosis, followed by immunohistochemical tests. The diagnosis of localized amyloidosis should always be integrated with blood tests, a bone marrow biopsy, echocardiography and digestive endoscopy to intercept systemic involvement.