外耳道アミロイドーシスの２例

Abstract

Amyloidosis is a relatively rare disease that is defined by extracellular deposition of amyloid. Although it causes disorders of various tissues and organs including the head and neck, little is known about the involvement of amyloid in external ear disorder. Here we report two case studies of amyloidosis in the external auditory canals. One patient was a 66-year-old female with ear itching. Multiple brownish nodules were seen in both ear canals. The other patient was a 46-year-old female with bilateral hearing loss. She had been receiving chronic hemodialysis treatment for 20 years. Her physical examination demonstrated brownish masses that occupied both ear canals and 30-dB conductive hearing loss in pure tone audiometry. The masses in both of her ears were excised to resolve the hearing impairment. Both patients' pathological findings for the ear masses were positively stained by Congo red, and they were diagnosed with amyloidosis. Immunohistochemical staining was performed in both cases. We identified the first case as localized cutaneous amyloidosis, and the second case as dialysis-related amyloidosis.