Pseudoxanthoma elasticum

Abstract

Background: Linear focal elastosis is an uncommon dermal elastosis that occurs predominantly on the back. Although first described in the lumbar region of elderly white men, more recent reports note similar findings on the trunk and limbs of adolescent Asian men.

Methods: We present a typical case of an eighty-three year old white man with a one-year history of asymptomatic linear yellow and erythematous plaques on his lumbar region.

Results: Light microscopic examination revealed skin with an unremarkable epidermis with coarsely clumped elastic fibers in the reticular dermis, which were highlighted by an elastic tissue stain.

Conclusion: The histopathologic differential diagnosis includes pseudoxanthoma elasticum, connective tissue nevus, elastofibroma, and solar elastosis. Although some of these diagnoses can be excluded by histologic examination, correlation with the clinical findings is necessary to arrive at the correct diagnosis of linear focal elastosis.

Linear focal elastosis is an uncommon dermal elastosis that was originally described as asymptomatic linear yellow plaques in the lumbar region in elderly white males 1. Recent reports have extended the spectrum of this entity to include red-yellow linear atrophic to raised plaques on the trunks and limbs of adolescent males, predominantly of Asian descent. Twenty-one cases of linear focal elastosis have been reported in the literature. We report an additional case of linear focal elastosis in an elderly male and review the literature.

Case Report

An eighty-three year old white male presented with a one-year history of asymptomatic yellow-red linear plaques involving the middle and lower back (Figure 1). Striae distensae were absent from the flexural and abdominal areas. No other significant skin lesions were noted. There was no history of recent weight gain or loss, nor had the patient been on any medications in the past year, including topical and systemic corticosteroids. His past medical history was significant only for carcinoma of the prostate, which was being treated with observation. Because the patient was concerned about his skin lesions, shave biopsies were performed to determine the nature of the plaques.

[FIGURE 1 OMITTED]

Hematoxylin and eosin (H & E) stained sections were unremarkable at scanning magnification. There was no epidermal hyperplasia or hyperkeratosis. The dermis did not show a significant inflammatory infiltrate, and there was no increase or decrease in the number of dermal fibroblasts or collagen (Figure 2). On higher magnification there was an increase in pale, fragmented eosinophilic fibers in the middle and deep reticular dermis, interspersed amongst normal-appearing collagen bundles (Figure 3). These pale fibers were highlighted by a Verhoeff-van Gieson stain, indicating that they were elastic fibers (Figure 4). Von Kossa stain for calcium was negative. Because these changes were subtle, the diagnosis of linear focal elastosis was not made until the third biopsy, in which the increase of dermal elastic fibers was most evident. Retrospective examination aided by the Verhoeff-van Gieson stain revealed that the increase in elastic fibers was present in the two earlier biopsies, although to a lesser degree.

[FIGURES 2-4 OMITTED]

The patient did not receive any therapy for his lesions, and they have remained stable over the last two years.

Discussion

The diagnosis of linear focal elastosis (LFE), or elastotic striae, was first introduced in 1989 to describe three elderly white male patients with linear yellow plaques on their back, whose biopsies showed increased amounts of clumped and fragmented elastic fibers in the reticular dermis without a significant alteration in collagen fibers (1). Subsequently, additional reports in the literature have classified a wide age range and ethnically diverse population of patients as having LFE (Table 1) (1-14). Men are more commonly affected than women. While most LFE lesions occur on the middle to lower back, cases have been reported that involve the legs (10,14). Increased dermal elastin occurs in other dermal elastoses, as well as in some cases of striae distensae (SD) (Table 2). While many of these entities have a distinctive histopathologic appearance, others may require clinicopathologic correlation to arrive at the correct diagnosis.

The etiology of LFE is unknown. The most widely accepted theory is that LFE may represent a type of SD. Other hypotheses are that LFE is a hamartomatous or nevoid proliferation of elastic fibers, or possibly an inherited skin disorder (4,8).

In support of the first theory, several cases of LFE have been reported adjacent to or merging with SD lesions (3,9,12). However, patients with LFE do not have associated weight changes or manifestations of steroid excess, conditions commonly associated with SD. Histologic examination of striae distensae shows an alteration in the amount and orientation of dermal elastin and collagen. The elastic and collagen fibers are oriented horizontally in the reticular dermis, with fine elastic fibers that increase in number and in thickness as the lesion evolves (15,17). One constant that is reported in SD but not in LFE is atrophy of the epidermis with attenuation of the rete ridge pattern and decreased elastic fibers in the papillary dermis.

More recently, some authors have classified red linear striae that are palpable to atrophic as LFE (11,13). Biopsies of these variant lesions do not show the marked increase in clumped and fragmented dermal elastic fibers described in the original cases of LFE; rather, elastic fibers tend to be decreased and finer, with a greater degree of fragmentation than normal The interpretation is that these red linear lesions are early evolving lesions of LFE. However, these cases may simply represent examples of adolescent striae, which eventually evolve into SD. Because the majority of these reported cases are in young Asian patients, SD in this skin type may not typically be pale in color and might exhibit a slightly darker coloration. Long-term follow-up of these younger patients would be valuable to test the hypothesis that linear focal elastosis is a variation of the natural evolution of striae distensae, as opposed to a unique disease process unto itself.

In summary, linear focal elastosis is an uncommon dermal elastosis that presents as linear raised yellow plaques on the back. Men are affected much more commonly than women, with most patients being advanced in age. Biopsies of the lesions reveal an increased in fragmented elastic fibers in the reticular dermis, which may be hard to appreciate without histochemical stains for elastin. It is important to recognize this entity and distinguish it from other dermal elastoses for both clinician and patient reassurance.

References

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(2.) Hagari Y, Mihara M, Morimura T, Shimao S. Linear focal elastosis. An ultrastructural study. Arch Dermatol 1991 Sep; 127(9):1365-8.

(3.) White GM. Linear focal elastosis: a degenerative or regenerative process of striae distensae? J Am Acad Dermatol 1992 Sep; 27(3):468.

(4.) Moiin A, Hashimoto K. Linear focal elastosis in a young black man: a new presentation. J Am Acad Dermatol 1994 May; 30(5 Pt 2):874-7.

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(7.) Palmer J, Madison KC, Stone MS. Asymptomatic linear bands across the back. Linear focal elastosis. Arch Dermatol 1995 Sep; 131(9):1070-4.

(8.) Tamada Y, Yokochi K, Ikeya T, Nakagomi Y, Miyake T, Hara K. Linear focal elastosis: a review of three cases in young Japanese men. J Am Acad Dermatol 1997 Feb;36(2 Pt 2):301-3.

(9.) Hagari Y, Norimoto M, Mihara M. Linear focal elastosis associated with striae distensae in an elderly woman. Curls 1997 Nov;60(5):246-8.

(10.) Breier F, Trautinger F, Jurecka W, Honigsmann H. Linear focal elastosis (elastotic striae): increased number of elastic fibres determined by a video measuring system. Br J Dermatol 1997 Dec;137(6):955-7.

(11.) Chang SE, Park IJ, Moon KC, Koh JK. Two cases of linear focal elastosis (elastotic striae). J Dermatol 1998 Jun;25(6):395-9.

(12.) Hashimoto K. Linear focal elastosis: Keloidal repair of striae distensae. J Am Acad Dermatol 1998 Aug;39(2 Pt 2):309-13.

(13.) Choi SW, Lee JH, Woo HJ, Park CJ, Yi JY, Song KY, Kim HO. Two cases of linear focal elastosis: different histopathologic findings. int J Dermatol. 2000 Mar; 39(3):207-9.

(14.) Ramlogan D, Tan BB, Garrido M. Linear focal elastosis. Br J Dermatol. 2001 Jul;145(1):188-90.

(15.) Watson RE, Parry EJ, Humphries JD, Jones CJ, Poison DW, Kielty CM, Griffiths CE. Fibrillin microfibrils are reduced in skin exhibiting striae distensae. Br J Dermatol 1998 Jun;138(6):931-7.

(16.) Tsuji T, Sawabe M. Elastic fibers in striae distensae. J Cutan Pathol 1988 Aug;15(4):215-22.

(17.) De Pasquale V, Franchi M, Govoni P, Guizzardi S, Raspanti M, Poppi V, Ruggeri A. Striae alba: a morphological study on the human skin. Basic Appl Histochem 1987;31(4):475-86.

(18.) Zheng P. Lavker RM, Kligman AM. Anatomy of striae. Br J Dermatol 1985 Feb;112(2):185-93.

ADDRESS FOR CORRESPONDENCE:

John C. Pui, MD

NYU School of Medicine

Dermatopathology Section

530 First Avenue, Suite 7J

New York, NY 10016

E-mail: jckpui@aol.com

Phone: 212-263-7250

Fax: 212-694-2991

JOHN C. PUI, MD (1), MARTHA ARROYO, MD (1), PATRICK HEINTZ, MD (2)

(1.) RONALD O. PERLMAN DEPARTMENT OF DERMATOLOGY, NEW YORK UNIVERSITY SCHOOL OF MEDICINE, NEW YORK, NY, USA

(2.) GREAT LAKES PATHOLOGISTS, S.C., WEST ALLIS, WI, USA

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