Agminate lichen aureus.

Lichen aureus is a rare variant of pigmented purpura, with a chronic and benign course. It is generally asymptomatic and often occurs in the lower limbs, presenting as erythematous brownish, coppery or golden macules and/or papules. The diagnosis is based on clinical and histopathological findings. The dermatoscopic pattern has been considered a useful tool in diagnosis presumption. We describe a case with a confluent morphological pattern, called agminate lichen aureus.

INTRODUCTION

Lichen aureus is a variant of chronic pigmented purpura. This group is composed of Schamberg's pigmented purpura, Gourgeot-Blum disease, Kapetanaski disease and Majocchi purpura.[1] These diseases are characterized by a reddish-brown appearance which corresponds histologically to hemosiderin deposition. These chronic pigmented purpuras present the same histological pattern: a variable degree of lymphocytic infiltrate in the upper dermis associated with hemosiderin deposits. Our report shows an uncommon confluent morphology, called agminate lichen aureus.

CASE REPORT

Male, 28-year-old, presenting a brownish 3cm lesion on the dorsal region of the right wrist, noted about 10 years ago (Figure 1). Its onset could not be correlated with trauma, medication or contact with any substance. The lesion appeared as an insect bite, initially reddish, and subsequently brownish in the center. There was no itching, soreness, discharge or other similar lesions on the body. The patient denied other diseases.

FIGURE 1

Agminate lichen aureus. Lesion on the right arm

Dermoscopy showed a copper-coloured amorphous area and absence of pigmented network (Figure 2). The histopathology evaluation showed sparse capillaries, associated with heavy subepidermal mononuclear inflammatory reaction in a lichenoid pattern (Figure 3). The histochemical staining demonstrated diffuse deposition of hemosiderin (Figure 4).

FIGURE 2

Agminate lichen aureus. Dermoscopy

FIGURE 3

Agminate lichen aureus. Subepidermal mononuclear inflamatory reaction (HE; x40)

FIGURE 4

Agminate lichen aureus. Dermal hemossiderin (blue) (iron pigment staining; x150)

DISCUSSION

Lichen aureus (LA) was described as a case study for the first time in 1958 by Martin. In 1960, Calman used the term LA to emphasize the yellow-golden hue often observed in these lesions. Although its cause remains unknown, its pathogenesis seems to be related to inflammation of the capillaries in the papillary dermis, with occasional endothelial proliferation; a possible vasculitis.[2] Speculation also exists about the etiology being related to trauma, infections, drugs or venous insufficiency.[3]

Lichen aureus usually presents as a solitary plaque, with color ranging from dark-brown, to copper and a golden hue. Most of the lesions are asymptomatic, but there are some reports of itchy or painful lesions. LA can affect any part of the body, but it is most frequently described in the lower limbs, followed by the upper limbs and the trunk. Linear or segmental presentations have also been described.[4] It has a predilection for young adults. The onset is sudden, but the course is chronic and can progress slowly or stabilize. Some authors have questioned its chronic and benign nature, suggesting that LA may progress to mycosis fungoids, but a follow-up of 23 patients did not identify any case with this progression.[5]

Dermoscopy has been an important tool for the clinical diagnosis of the purpuras.[6] The findings include brownish or coppery-red amorphous area, oval or circular red spots, some gray spots, globules and a network of brownish to gray interconnected lines.

After reviewing the literature, we found that agminated lichen aureus had been described only once (in the United Kingdom).[7] This is the first case reported in Brazil.

We should consider in the differential diagnosis the other aforementioned purpuras and Langerhans cell histiocytosis. Two possible differential diagnoses for the agminated presentation are the Spitz nevus and the "hobnail" hemangioma, in which the histopathological study is essential for the differentiation.[8,9,10]

The treatment of LA is difficult. The therapeutic arsenal includes PUVA, calcineurin inhibitors and corticosteroids. In the case reported, after the incisional biopsy was performed and lichen aureus was confirmed, the residual lesion underwent intense pulsed light with 12ms and 18J fluency, and disappeared almost completely.