Dermatology Online Journal

Circumscribed lenticular anetoderma in an HIV-infected man with a history of syphilis and lichen planus
Raegan Hunt MD PhD, Julie Chu MD, Rishi Patel MD, Miguel Sanchez MD
Dermatology Online Journal 17 (10): 2

Department of Dermatology, New York University, New York, New York

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Abstract

Anetoderma is an uncommon dermatosis that manifests as discrete foci of well-circumscribed, atrophic skin. The condition can be idiopathic or can be secondary to a number of associated cutaneous diseases. Whereas the pathophysiologic mechanisms remain unknown, anetoderma results from diminished elastic fibers in the dermis. We present an unusual case of localized, lenticular anetoderma in a man with HIV, a history of syphilis, and lichen planus. Both of these infections have been associated with anetoderma. Although his lesions are vaguely reminiscent of a variant of syphilitic anetoderma described in the 1930s, they are confined to a smaller anatomic distribution, differ in size, and have a papular appearance. As anetoderma can develop in the context of infectious disease, a diagnosis of anetoderma should trigger a thorough examination and evaluation for treatable concomitant illnesses.

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History

Figure 1

A 63-year-old man presented to the Dermatology Clinic at Bellevue Hospital Center for treatment of a pruritic eruption that consisted of violaceous, hyperkeratotic papules and plaques on the lower legs, which was confirmed histopathologically to be hypertrophic lichen planus. Incidentally, during the skin examination, many small, skin-toned papules were noted on his lower back. The patient denied current or previous pruritus or pain in the area. Although he was unaware of the presence of these lesions, he felt certain that they did not appear during childhood or young adulthood. Review of systems was negative. Past medical history included human immunodeficiency virus (HIV) infection, hepatitis C virus infection, and treated syphilis of undetermined latency. He had no history of Lyme borreliosis. His only medication was efavirenz/emtricitabine/tenofovir in a combined tablet. No family members have a similar skin condition.

Physical examination

Numerous, skin-toned, discrete, well-demarcated, irregularly-shaped, 2-to-8-mm, oval-to-round papules were confined to the central portion of the lower back. On palpation, the lesions were soft. A ring of normal surrounding skin was detected upon compression of each papule. A few, slightly-atrophic, hypopigmented macules were noted on the central portion of the upper back. Similar lesions were not found on the remainder of the total skin examination. Flat-topped, violaceous-to-hyperpigmented papules and small plaques were present on the anterior aspects of the lower legs. Oral mucosa demonstrated no leukoplakia or other abnormalities.

Laboratory data

An ELISA test was reactive for antibodies to human immunodeficiency virus-1 (HIV-1). Nucleic acid based sequence amplification (HIV-1 viral load) did not detect RNA HIV-1 particles. CD4+ T-lymphocyte cell count was 586 cells/mm³. A rapid plasma reagin test titer measured 1:8. The treponema pallidum particle agglutination assay was reactive.

Histopathology

Figure 2

There is a superficial, perivascular, lymphocytic infiltrate. A Verhoeff-van Gieson stain shows diminished elastic fibers in the papillary dermis.

Discussion

Anetoderma, which also is termed macular atrophy, is an uncommon, benign skin condition that results from focal reduction of elastic fibers in the dermis. Clinically, it presents as multiple, well-circumscribed areas of flaccid skin, which may appear depressed, demonstrate a wrinkled skin surface, or protrude in a sac-like manner. Classic lesions measure from 0.5 cm to 2.5 cm in diameter and predominantly appear on the neck, upper extremities, or trunk. Variable numbers of these atrophic lesions may be present.

Histopathologic examination demonstrates a perivascular, lymphocytic infiltrate that is associated with diminished elastic fibers in the dermis, which is appreciated after processing with special elastic-tissue stains. Phagocytosis of degraded elastic fibers by macrophages has been observed using electron microscopy [1]. The pathogenesis of anetoderma is poorly understood. The focal decrease in dermal elastic tissue may be a result of increased destruction or decreased synthesis of elastic fibers. Hypotheses for the pathogenesis of anetoderma include: increased release of elastolytic enzymes in response to pathologic triggers, degradation of elastic tissue after ischemia from microthromboses, and dysregulation of metalloproteinases or serpins (elastolytic enzyme inhibitors) [2].

Primary anetoderma develops within normal skin whereas secondary anetoderma appears at the sites of lesions of a number of disease processes. An extensive list of infectious (acne, varicella, Lyme borreliosis, Hansen disease, syphilis), autoimmune (lupus erythematosus), inflammatory (arthropod bites), neoplastic (urticaria pigmentosa, cutaneous lymphoma), drug-induced (penicillamine) and deposition based (amyloidosis) skin diseases have been implicated in secondary anetoderma [3]. Some authors have classified anetoderma that occurs at previously unaffected skin sites in individuals with associated systemic disorders, which include HIV infection and antiphospholipid syndrome, as secondary. Although our patient is infected with HIV, the anetoderma should be considered primary because there is no history of skin disease in the affected areas and no inflammatory changes are found in the biopsy specimen. In many cases, it is difficult to establish the specific cause of anetoderma. Owing to its discordant distribution of predilection and the absence of pruritus in the affected area, the lichen planus is unlikely to have contributed to the anetoderma. Possible explanations for the anetoderma in our patient include the history of prior syphilis infection and HIV infection.

Although syphilis was the most common cause of anetoderma in the early 1900s, it has not been established whether destruction of elastic fibers is mediated by treponemal invasion, inflammatory changes, or anticardiolipin antibodies [4]. Although syphilitic anetoderma typically occurs in secondary, and rarely in tertiary, syphilis and congenital syphilis, it has not been reported to develop during the latent stage in the absence of previous skin lesions [5]. In 1931, two distinct clinical subtypes of syphilitic anetoderma were described: one was characterized by numerous, subtle, atrophic lesions in a widespread, pityriasiform distribution, and the other consisted of fewer, well-defined, convex, atrophic lesions that involved the back [6]. Although our patient had serologic evidence of syphilis and the lesions somewhat resemble the latter variant of syphilitic anetoderma, the absence of a history of secondary luetic lesions and the size of the anetodermic papules mitigates against this infection as the responsible etiology. In addition, whereas an eruption of lenticular papules has been described in secondary syphilis, the lesions are characterized by a diffuse distribution and would unlikely result in anetoderma that is confined to a small area [7].

The grouped pattern of the lenticular atophic papules in a circumscribed distribution is unusual. Our case differs from other disorders of dermal elastic tissue that present with papules. The lesions of papular elastorrhexis develop by early adulthood and consist of non-follicular, firm, 1-to-5-mm papules that are evenly scattered over the trunk. Perifollicular elastolysis presents as small papules that are centered around follicles on the face or upper back, but the lesions of our case did not have a perifollicular distribution. Nevus anelasticus is an attractive clinical consideration since the lesions are clustered; however, the atrophic lesions are larger and less grouped than they are in our case.

A few cases of classic primary anetoderma associated with HIV infection have been reported [2, 8-11]. It has been theorized, without supportive scientific evidence, that anticardiolipin autoantibodies, which also were present in these cases, contributed to the development of anetoderma through direct endothelial damage or complement activation and immune-complex formation [9]. Others have proposed that anetoderma could result from increased matrix metalloproteinase production induced by HIV infection or from the effects of non-nucleoside reverse transcriptase inhibitors on matrix metalloproteinases [4]. Owing to the small number of reported cases, it is difficult to develop strong conclusions regarding the incidence or behavior of elastic tissue disorders in the HIV-infected population [12]. However, it is noteworthy that in some of these cases, anetoderma occurred in patients with CD4+ T-lymphocyte cell counts that were greater than 200 cells/mm³ and was the presenting sign of HIV infection [8, 9].

Because anetoderma may be caused by or associated with a treatable infectious disease, this diagnosis should prompt a thorough physical examination, risk evaluation, and appropriate laboratory testing.

References

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12. Sanchez M. Editorial Comment: Anetoderma and HIV infection- a little known comorbidity. AIDS Read 2006; 16: 94

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