A Case of Lichen Amyloidosis Successfully Treated with Alitretinoin.

Sir,

A 59-year-old Korean man presented with 2-year history of brownish-to-gray colored lichenified and hyperkeratotic papulopatches accompanying pruritus on his back and both arms [Figure 1a]. His medical history included asthma and allergic rhinitis. There was no relevant family history. Histological examination revealed deposits of amorphous materials within the broadened papillary dermis [Figure 1b]. Both Congo red (CR) and cytokeratin (CK) 5/6 immunostaining exhibited positive reaction in the amorphous area [Figure 1 and d]. Additionally, apple-green birefringence was observed under polarized microscopy with CR. He had no response to 7-week treatment of cyclosporine (50–100 mg/day) and methylprednisolone (2 mg/day) along with applying methylprednisolone aceponate cream. However, after 5-week treatment of oral alitretinoin (30 mg/day), he started to show response to treatment. Prominent improvement on his skin lesion induced by taking alitretinoin for 32 weeks is shown in [Figure 2]. The informed and written consent for publication of his photography and clinical information was obtained from the patient.

Figure 1

Brownish-to-gray colored lichenified and hyperkeratotic scaly papulopatches on the arm (a). Hyperkeratosis, papillomatous epidermis and collection of amorphous material surrounded by a few macrophages within the widened dermal papillae (b, H and E, x200).. Focal positive reaction within the papillary dermis in both Congo red (c, Congo red, X200). and CK 5/6 immunostatining (d, CK 5/6, X200)

Figure 2

Skin lesions at the time of his first visit showing typical features of lichen amyloidosis (a and b). Flattened skin lesions with relatively brightened color after 32 weeks of daily oral alitretinoin 30 mg treatment (c and d)

Lichen amyloidosis (LA) is a subtype of primary localized cutaneous amyloidosis and it typically presents itchy hyperkeratotic papules that can coalesce into plaques. Histologic findings of LA include hyperkeratosis, irregular acanthosis, hyperpigmentation of basal keratinocytes, elongation of the rete ridges, and deposits of amyloid confined to the dermal papillae.[1] CR stain can help identify the presence of amyloid deposit because CR-stained amyloid appears orange-red under light microscopy and apple-green birefringence under polarized light microscopy. And, CK5/6 positivity in amyloid deposits can confirm that the amyloid is derived from keratinocytes.[2]

Although several therapeutic options, such as corticosteroid, oral antihistamine, cyclosporine, retinoid, and colchicine, were reported as efficacious for LA, there are no definitive recommendations on desirable management.[3] Retinoids are known to have therapeutic effects in LA by suppressing the formation of keratin-derived amyloid. Retinoids can restrict amyloid production by reducing inflammatory injuries to the basal keratinocytes and decreasing regulatory factors, such as heat-shock proteins and apolipoprotein E, known to be associated with keratin-derived amyloid production. Retinoids also inhibit epidermal proliferation and promote the differentiation of keratinocytes, inducing the improvement of acanthosis and hyperkeratosis.[4] A few LA cases successfully treated with alitretinoin, one of the retinoids, were previously reported.[45] Alitretinoin acts without suppressing sebum secretion, unlike other retinoids including isotretinoin or acitretin.[4] Decreased sebum secretion can cause xerosis cutis and aggravation of pruritus, so alitretinoin may be more preferable treatment option for LA than other retinoids. Our patient was confirmed as keratinic amyloidosis because CK 5/6 immunostaining showed positive reaction in the CR positive area. Therefore, it was reasonable to speculate that alitretinoin might have a therapeutic effect on his skin lesion. Indeed, his skin lesion and pruritus were improved by alitretinoin without any considerable side effect.

In conclusion, we reported a case of LA successfully treated with alitretinoin. Although alitretinoin is principally used for severe hand eczema, it can be also considered as an efficacious and safe treatment for LA referring to the previously reported cases[45] and our patient. However, this is a conclusion based on anecdotal evidences, and further studies seem to be need in order to demonstrate the efficacy and safety of alitretinoin for LA more reliably.

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