Clinical and morphological features of localized laryngeal amyloidosis

Abstract

Introduction. Amyloidosis is a disease characterized by extracellular deposition of insoluble fibrils composed of an abnormal protein, amyloid. This protein builds up in various tissues and organs and interferes with their function leading to atrophy and sclerosis. Amyloidosis is usually a systemic disease. However, there are case reports of localized amyloidosis. Localized laryngeal amyloidosis is a rare condition accounting for approximately 15% of localized amyloidosis. The aim of the research was to describe morphological features of localized laryngeal amyloidosis. Materials and methods. We analyzed clinical findings, biopsy, and surgical specimens of 6 patients with localized laryngeal amyloidosis. Amyloid deposits were detected in tissue sections with Congo red stain with polarized light microscopy. We performed immunohistochemical analysis with monoclonal and polyclonal antibodies to detect different amyloid types. Results. Laryngeal amyloidosis was diagnosed in 4 male and 2 female patients aged from 44 to 62 (the mean age was 54 years). We found amyloid deposits in the interstitial spaces and tumor-like masses; in polarized light, amyloid showed a bright apple-green birefringence. Inflammatory cell infiltrate and multinucleated giant cells were visualized in most cases. Based on the immunohistochemical typing results, 4 patients had AL-kappa amyloidosis and 2 patients were diagnosed with AL-lambda amyloidosis. The disease recurrence was reported in 2 cases. Conclusion. In the head and neck area, the larynx is the most common site affected by localized amyloidosis. AL-kappa amyloidosis prevailed in our study, most of them being in men. In view of high recurrence rates, a long-term follow-up is needed after the amyloid deposit excision. Keywords: amyloidosis, larynx, amyloidoma, localized amyloidosis, immunohistochemistry