Decade-Long Progression of Localized Amyloidosis from the Larynx to the Nasal Cavity-A Case Report.

Localized amyloidosis of the upper aerodigestive tract is an uncommon and benign condition characterized by extracellular amyloid deposition. While the larynx is the most frequently involved site, progressive, multifocal mucosal involvement remains exceedingly rare. We report the case of a 58-year-old male initially diagnosed with localized laryngeal amyloidosis confirmed via Congo red staining. The initial laryngeal lesions were excised using conservative endoscopic surgery to both confirm the diagnosis and alleviate symptoms. However, no additional treatment was recommended by the rheumatology department since the patient's further evaluations did not indicate a diagnosis of systemic amyloidosis. Over an 11-year follow-up period, sequential progression to the nasopharynx was observed after five years and to the nasal cavity after 11 years. The patient remained free of systemic involvement throughout, confirmed by comprehensive evaluations including serum and urine immunofixation, renal and hepatic panels, and 24-hour urine analysis. Symptomatic relief was achieved with a series of conservative surgical interventions addressing airway and auditory symptoms. The patient remains under active surveillance. This case highlights a rare, progressive pattern of localized amyloidosis involving contiguous mucosal sites in the upper aerodigestive tract. It underscores the importance of long-term follow-up, systematic evaluation to exclude systemic disease, and the efficacy of conservative surgical management. To our knowledge, this is the first reported case of progressive, segmental spread of localized amyloidosis involving the larynx, the nasopharynx, and the nasal cavity over more than a decade.