Unilateral Isolated Primary Cutaneous Amyloidosis of the External Auditory Canal.

Isolated primary cutaneous amyloidosis (PCA) of the external ear is extremely rare. We describe the case of a 65-year-old woman presenting with itching within the left external auditory canal (EAC). Otoscopy revealed a 3 mm whitish lesion involving the cartilaginous portion of the left EAC. The lesion was excised. Histological and immunohistochemical features were consistent with keratinic amyloidosis. A clinical workup was negative for systemic amyloidosis. As far as we know, only nine cases of PCA exclusively involving the EAC have been reported. The frequent occurrence of itching in these patients and the keratinic nature of the amyloid support the role of chronic stimulation/irritation in the pathogenesis of isolated amyloidosis the EAC.