Immunophenotyping Oral Amyloidosis for the Precise Identification of the Biochemical Forms: A Retrospective Study

Background: Amyloidosis refers to a group of systemic and localized disorders associated with the accumulation of misfolded protein aggregates called amyloids in different parts of the body. Owing to the existence of multiple forms of amyloids with similar tertiary structures, precise identification of their biochemical form is critical for correct therapy. Objective: This retrospective study aimed to determine whether typing of oral amyloid deposits can help diagnose a serious systemic condition in the early phase of the disease Methods: All histopathologically confirmed cases of amyloidosis managed over a 14-year period (January 1, 1997 to December 31, 2011) were retrieved for analysis. Two board-certified oral and maxillofacial pathologists reviewed the histopathological findings of amyloidosis on the basis of its classic Congo red staining characteristics. This was followed by immunohistochemical analysis of biopsy samples using a panel of antibodies specific for different forms of amyloidosis. Results: The most common location of amyloidosis was the tongue, and women were more commonly affected than men. The patient age ranged from 11 to 83 years (average 59.3 years). In patient 9, light-chain and pre-albumin (transthyretin) antibodies were related to arthritis and senile amyloidosis, respectively. The biopsy sample of patient 10, who was reported to have multiple myeloma, was positive for light chains and beta 2 microglobulin. All other samples exhibited localized (solitary) amyloidosis. Conclusion: Histological analysis coupled with immunostaining with a panel of specific antibodies might assist in identifying early systemic amyloidosis in patients with localized oral forms of the disease.