Lichen amyloidosis (LA) is the most common form of primary cutaneous amyloidosis. It’s a very pruritic hyperkeratotic and
coalescent papules usually localized on the anterior tibiae. The diagnostic is clinical, dermoscopy reveals two major dermoscopic
patterns characteristic of LA, namely, ‘central hub’ and ‘scar-like’.
Papular amyloidosis, formerly called lichen amyloidosis (LA)
is the most common form of primary cutaneous amyloidosis,
histologically characterized by accumulation amyloid deposits
in the dermis. It’s a very pruritic hyperkeratotic and coalescent
papules usually localized on the anterior tibiae. We reported the
case of a 70 year old man with 2 years history of a pruritic papular
eruption on the lower legs (Figure 1).
Figure 1: The clinical picture of a patient with lichen
amyloidosus on the lower limb.
An 80 years old woman with antecedents of high blood
pressure and diabetes has consulted for pruriginous lesions of the
anterior surfaces of the legs and knees evolving since 2 years. The
clinical examination revealed multiple yellowish papules firm and
rough on palpation on the lower limbs. The diagnosis of LA has
been made and was confirmed by cutaneous biopsy with compact
orthohyperkeratosis, acanthosis and amorphous amyloid deposits
in the dermal papillae (Figure 2A). Dermoscopic examination
showed a whitish scar-like center with structureless morphology
surrounded by some brownish dots which is very specific to LA.
Lichen amyloidosis is the most frequent type of primary
localized cutaneous amyloidosis [1]. It is clinically characterized
by pruritic keratotic distributed frequently on the anterior tibiae
and occasionally on the trunk and upper extremities [1-2]. The
differential diagnosis is made with mucinosis, lichen simplex
chronicus and prurigo nodularis [1-3]. The diagnosis is clinical
(Figure 2B). A skin biopsy should be reserved for evolving
lesions. Chuang et al. [1] described two major dermoscopic
patterns characteristic of LA, namely, ‘central hub’ and ‘scar-like’.
Two subtypes of ‘scar-like’ pattern were noticed, including one
resembling a volcanic crater and the other displaying completely
structureless morphology as we found in our patient [1-4].