Primary cutaneous amyloidosis of the auricular concha
Primary cutaneous amyloidosis of the auricular concha is generally not associated with underlying systemic amyloidosis or other systemic disease; however, auricular lesions can be seen in the setting of other forms of amyloidosis including systemic amyloidosis. There have been reports of this entity occurring in patients on hemodialysis.
E85.9 – Amyloidosis, unspecified
201337008 – Amyloidosis of skin
733729003 – Primary localized cutaneous amyloidosis
Differential Diagnosis & Pitfalls
- Basal cell carcinoma – May present as an asymptomatic, small papule in the auricular concha. These entities are histopathologically distinct.
- Trichilemmomas of Cowden syndrome – Warty, skin-colored or erythematous papules that can appear on the ears and face. Trichilemmomas are often multiple and have a distinct appearance on histopathology.
- Cylindroma – Generally multiple papules and nodules that are often pink or erythematous on the head and neck. Cylindromas have a distinct histopathologic appearance.
- Angiolymphoid hyperplasia with eosinophilia – This entity generally presents as variably sized erythematous papules, nodules, or plaques that can occur on or around the ears. Lesions are often grouped and can be painful or pulsatile. Angiolymphoid hyperplasia with eosinophilia has a specific histopathologic appearance.
- Seborrheic keratosis
- Infundibular or epidermal inclusion cyst
- Discoid lupus erythematosus – This often presents in the conchal bowls but is generally a scaly or sclerotic plaque as opposed to papules. The histopathologic findings of discoid lupus are distinct from those of primary cutaneous amyloidosis of the auricular concha.
- Relapsing polychondritis – This entity can result in erythema and nodularity of the ear that generally spares the lobule. While this entity can involve the conchal bowl, it generally also involves the helical rim. Relapsing polychondritis typically has a waxing and waning course, which would not be seen with primary cutaneous amyloidosis of the auricular concha.