Patient Presentation
A 40-year-old woman presented with a 2-month history of a new scar on the left side of her forehead. The patient reported a history of abrasions from minor traumas to the forehead but denied any serious head trauma, seizures, dysphagia or Raynaud’s phenomenon. Her past medical, social and family histories were unremarkable. On physical examination, there was an atrophic linear groove with a hyperpigmented border starting at her left eyebrow and lengthening vertically into her scalp with a linear area of hair loss extending over the left frontoparietal scalp. Aside from residual scars on the right side of the forehead, there were no signs of facial atrophy, neurological abnormalities, exophthalmos or other skin lesions.

Diagnosis: En Coup De Sabre
En coup de sabre (ECDS) is a linear scleroderma occurring in the frontal and parietal areas of the face. Its name derives from the similarity of this lesion to one that would occur with the cut of a sword. Addison1 originally noted the initially firm feature of ECDS lesions in 1854; he called it a “true keloid.”

Scleroderma is characterized by the obliteration of the microvasculature and fibrosis of the connective tissue in the skin, lungs, gastrointestinal tract, kidneys and heart.2 Scleroderma is classified as localized or systemic. Localized scleroderma only involves the cutaneous tissue and mainly encompasses morphea and linear scleroderma (see “Classification Systems for Localized Scleroderma,” on page 65), while systemic scleroderma can involve the skin as well as other organ systems. Linear scleroderma is a variant of localized scleroderma and can be differentiated by its band-like appearance and propensity to involve the deeper skin layers and underlying structures in the limbs. ECDS is a form of linear scleroderma involving the frontoparietal area. Parry-Romberg syndrome (PRS) or idiopathic progressive facial hemiatrophy is controversially considered a form of linear scleroderma whose clinical features overlap with ECDS.3 The characteristic features include facial hemiatrophy, alopecia, seizures and exophthalmos.

Clinicopathologic Presentation
The estimated incidence of localized scleroderma is 2.7:100,000.4 Women are more likely to present with this disease, and often before the second decade.5 There are no geographic or ethnic predispositions.

ECDS initially presents with an erythematous patch, then the skin hardens and becomes yellow-white, smooth and depressed.6 Loss of hair, anhydrosis, and hypo- or hyperpigmentation are common associated findings.7 ECDS is usually unilateral, although rare bilateral8 and trilinear manifestations have been reported.9 It generally arises in the forehead and may extend as far as the neck.10

The ECDS atrophy can extend to involve the subcutaneous tissue, muscles and bone.4 Additionally, the eye, teeth and tongue can be affected.4,8,11,12 When the brain becomes involved, the gray and white matter changes and intraparenchymal calcification may also be noted, which can symptomatically manifest as seizures and other neurological deficits.13,14,15

ECDS can be diagnosed clinically and confirmed histologically.6 It is crucial to perform a deep biopsy involving the dermis, panniculus and fascia. Histologically, ECDS is characterized by the deposition of collagen in the dermis and subcutis, inflammatory perivascular and diffuse infiltrate (predominantly seen in early lesions and composed of lymphocytes, macrophages and plasma cells), small vessel wall thickening and lumen narrowing.16

Brain MRI is the screening test of choice to determine central nervous system involvement in ECDS.7 The diagnosis can be further supported with laboratory results, including antinuclear antibodies,17 anti–ss DNA,18 eosinophilia,19 elevated IgG and C2 complement deficiency.4

Differential Diagnosis
PRS is a disorder that has similar clinical characteristics and has often been confused with ECDS.3 Some authors propose that the two conditions may overlap.3,13,20 PRS exhibits hemifacial atrophy that can extend to the tongue, gingiva and palate.6 In this syndrome, the skin is easily pliable, soft and thin.6 PRS is mainly distinguished histologically by initially involving the subcutaneous tissue and only later involving the dermis.6,10 Other distinguishing factors include higher frequency of cutaneous hyper/hypo-pigmentation and alopecia in ECDS patients versus higher frequency of ocular changes and complete hemifacial involvement in PRS patients. Additionally, in a study designed to differentiate these two disorders, the histological examination revealed that the majority of patients with ECDS had connective tissue fibrosis, adnexal atrophy, and mononuclear infiltrates, while patients with PRS exhibited a few of these findings.6

Other cutaneous entities that may mimic ECDS include bandlike melasma, which can be differentiated by the absence of atrophy and sclerosis, and keloid, which can be ruled-out via clinical history.1,21

Etiologic Theories
The etiology and pathogenesis of ECDS is unknown. However, multiple triggering factors have been implicated including infection, trauma, surgery and stress.22

Localized scleroderma has been linked to Borrelia burgdorferi infection in Germany and Japan; however, this is an unlikely pathogen in the United States because the proposed responsible genotypes of Borrelia are not encountered in North America.23

The histopathologic findings of anomalous, ectatic vessels in cerebral lesions of ECDS have been used as evidence that this is a neurocutaneous syndrome that arises from developmental anomalies. This is supported by the predilection of skin lesions to form along dermatomal lines and the co-existence of other developmental anomalies, such as spina bifida.14 The argument that there is a predisposition to ECDS that begins during embryogenesis is further supported by findings of this disorder along the Blaschko’s lines, the developmental cleavage lines.24

Others hypothesize that ECDS is an inflammatory or immune-mediated process.7,13 The presence of intrathecal IgG and oligoclonal bands in cerebrospinal fluid,25 neuropathological findings of inflammatory cerebral tissue, MRI showing resolution of intracerebral lesions with immunosuppressive treatment, and remittance of clinical symptoms with immunosuppressive treatment, all indicate an inflammatory process.13 Additionally, the frequent presence of anti-nuclear antibodies, evidence of inflammatory infiltrates within the skin lesions,7 concurrence with systemic lupus erythematosus26 and exacerbation of symptoms during pregnancy,25 all point toward a potential autoimmune origin.7

Various Treatments
There are no standard guidelines for treating ECDS. Treatment modalities are generally directed at immunosuppression and rectification of disfigurement with surgery and other cosmetic modalities.9,10,27 The initial management usually consists of topical, oral or intravenous steroids. Although D-penicillamine (Cuprimine) has been effective in softening ECDS lesions, it has been ineffective in halting the progression of facial atrophy.12 Methotrexate, when given in conjunction with initial doses of intravenous steroids, also mollified the skin lesions in patients with localized scleroderma.28 In addition, UVA-1 phototherapy can be considered due to its success in softening and clearing sclerotic lesions of localized scleroderma through the induction of collagenase in sclerotic tissue.29 The administration of azathioprine (Imuran) resulted in a notable decrease in autoantibodies and prevented further progression of ocular disease linked with ECDS.12 Another patient with ocular complications has been treated with interferon gamma (Actimmune), resulting in the cessation of pain and deterioration in visual acuity and improvement in visual field defects.11

Course and Prognosis
ECDS is a chronic disease that often presents in childhood and progresses over the first 2 years and may continue to spread or deepen over the next 5 to 6 years.7,14 Atrophy of the deeper tissue layers and CNS involvement are more likely to occur with an early onset of the disease.20 However, based on the reports of CNS symptoms occurring decades after the onset of ECDS,14 it is recommended to follow these patients long-term to monitor for disease progression.