High Frequency of Genital Lichen Sclerosus in a Prospective Series of 76 Patients With Morphea:  Toward a Better Understanding of the Spectrum of Morphea FREE

Morphea and lichen sclerosus (LS) are 2 entities that are characterized clinically by plaques of indurated, sclerotic, and dyschromic skin and pathologically by an inflammatory dermal infiltrate and dermal fibrosis. Their cause is largely unknown, although both genetic factors, such as predisposing HLA alleles, and environmental factors, such as infection with Borrelia burgdorferi, have been involved in some cases.^1- 15 Autoimmune diseases and/or stigmata are more frequent in patients with morphea or LS than in unaffected persons.^1,16- 20

Different clinicopathologic variants of morphea, summarized in Table 1, have been described.²¹ Morphea involves the skin, but the extremities, the face, and the aerolar area are usually spared, while LS usually involves the genital mucosa. Skin involvement can occur in LS but is rare.

Although there are some similarities between morphea and LS, their exact relationship remains debated. Some authors²² consider that LS is a superficial variant of morphea occurring mostly in the genital area, whereas others^23- 25 consider that they are 2 unrelated entities. In some cases involving the skin, referred to as “white spot disease, ” the differential diagnoses between morphea and LS can be impossible. However, lesions occurring on genital mucosa are usually considered synonymous with LS. Yet, to our knowledge, no study has evaluated the frequency of LS in patients with typical morphea. Furthermore, in clinical practice, genital examination is not systematically performed in patients with morphea. Neither is it recommended in most dermatology textbooks.^24,26- 27 However, it is important to diagnose genital LS if present, because this entity bears a significant risk of squamous cell carcinoma.^28- 30 This risk can probably be reduced by early and sustained treatment with topical corticosteroids.^31- 33 Thus, the aim of this study was to evaluate the frequency of genital LS in patients with morphea.

This is a prospective multicenter study. Patients were recruited from November 1, 2008, through June 30, 2010, in the departments of dermatology from 4 French university hospitals: Strasbourg, Montpellier, Tenon Hospital Paris, and Henri Mondor Hospital Cr éteil. Patients were included if the diagnosis of morphea was confirmed clinically by an experienced dermatologist or after a skin biopsy. Data were collected on a standardized questionnaire and included age and sex. The various forms of morphea were specified according to the classification used in this study (Table 1): plaque, linear, and/or generalized. The number of plaques, their size, their location, their clinical description, and the functional consequences were reported. When patients had both plaque morphea and linear lesions, they were classified as having linear morphea. The genital area was examined in every patient by an experienced dermatologist to search for signs of LS. The diagnosis of LS was accepted in the case of typical clinical and/or histopathologic findings. Patients with systemic sclerosis as defined by the criteria of the American College of Rheumatology were not included in this study.

The control patients in our study consisted of patients seen in the dermatology department for a reason other than morphea and who had a complete skin and mucosal examination. Most were followed up as part of surveillance of cutaneous malignancies. Some had inflammatory diseases, such as psoriasis or lupus erythematosus.

Statistical analyses were performed in collaboration with the Secteur Biostatistiques et M éthodologies at the Universit é de Strasbourg. Before starting the study, we estimated that the number of patients to be included, assuming that the incidence of LS in the general population is 1 in 300 to 1 in 1000 and that the expected difference in prevalence would be 10%, would be 50 to 80 patients with a power of 95%.

The main objective was to compare the frequency of genital LS in patients with morphea with that of the control group. For this purpose, a comparison test was conducted between the frequency of genital LS in these 2 groups. The odds ratio was calculated by the Fisher exact test. We compared the age and sex between case patients and the control group by the χ² method. Under French law, this type of study, which does not involve any invasive investigation but relies on a questionnaire performed during a regular consultation, does not need the approval of the institutional review board.

We included 76 patients with morphea. This group consisted of 18 men (24%) and 58 women (76%). The mean (range) age was 54 (13-87) years. The mean (range) duration of morphea was estimated to be 7.9 years (6 months –36 years), but it was not specified in 46 cases. The diagnosis was made on typical clinical findings in 50 patients and was confirmed by a biopsy in 26.

One hundred one controls were included (68 women and 33 men). The mean (range) age was 57 (1-87) years. There was no significant statistical difference between the patients and the control group for age (P  =  .44) and sex (P  =  .30).

Forty-nine patients had plaque morphea, 18 had linear morphea, and 9 had generalized morphea. In only 1 patient, the clinicopathologic findings were typically those of extragenital LS. This patient had pathologically confirmed plaques of both morphea and extragenital LS. The clinical characteristics in these patients are summarized in Table 2.

Quiz Ref IDThree patients (3%) in the control group and 29 patients (38%) with morphea had LS. Thus, compared with the frequency in the control group, genital LS is significantly more frequent in patients with morphea, with an odds ratio of 19.8 (95% CI, 5.7-106.9; P   <  .001).

The frequency of LS according to type of morphea is illustrated in Figure 1. Quiz Ref IDForty-five percent of patients with plaque morphea and only 6% of patients with linear morphea had genital LS (P   <  .001).

Twenty percent of patients had genital pruritus. Interestingly, none of the patients spontaneously complained about this symptom, which was always revealed through specific questioning.

Twenty-seven patients were incident cases of morphea who did not see a dermatologist before this study and in whom diagnosis of morphea was previously not established. Their mean (range) age was 50.8 (13-84) years, and the female to male ratio was 21:6. The mean (range) duration of morphea was estimated as 4.6 years (6 months –33 years). Of these 27 patients, 13 (48%) had genital LS. The mean (range) age of the 13 patients with genital LS was 64.9 (14-84) years. Ten of the 13 patients had plaque morphea (Figure 2) and 3 had generalized morphea.

This study shows that genital LS is significantly more frequent in patients with morphea than in controls and that LS is found with an unexpected high frequency of 38% in patients with morphea. The prevalence of LS in the population is difficult to evaluate, but it is estimated from 1 in 300 to 1 in 1000.

Quiz Ref IDThus, the frequency of LS in the controls of this study is ten times higher than the frequency usually estimated to occur in the general population. This can be explained by a selection bias in our control group of patients mainly recruited in a dermatology department and examined by experienced dermatologists. However, it should also raise some doubt about the usually published data regarding prevalence rates of LS in the general population. It might be that the exact prevalence of LS in the general population is largely underestimated. Indeed, evaluation of prevalence is difficult because the manifestation may be asymptomatic, patients do not consult for discomfort because of the genital location of the lesions, and many physicians are not familiar with this entity and are thus unable to correctly diagnose it. Only a systematic genital examination by an experienced practitioner will provide valuable prevalence rates. In any case, this unusually high frequency of LS in the control group could have harmed this study by lowering our ability to demonstrate a difference in the frequency of genital LS between controls and patients with morphea. This was not the case because there is still a large and significant difference.

Genital LS was significantly more frequent in patients with plaque morphea than in patients with linear morphea. This observation further supports the fact that those 2 entities might result from different pathomechanisms. Only 1 patient with linear morphea had associated LS. There were, however, too few patients with linear morphea included in this study to draw any definitive conclusion about a possible association. Patients with plaque morphea are those with the highest risk of associated genital LS, with occurrences in about 45% of patients. Furthermore, when we restrict our analysis to patients with incident morphea, that is, those who were not diagnosed with morphea before entering this study, we find a comparatively high frequency of LS of 48%. This fact could suggest that LS usually precedes morphea. The association between morphea and LS has been reported previously, mainly in patients with plaque morphea,^34- 40 but it was reported only once in a case of linear monomelic morphea in a young boy.⁴⁰ In most cases, however, the LS was extragenital.^{35,37- 39,41} Only 1 study³⁵ reported 7 cases of patients with morphea and genital LS. Quiz Ref IDThe fact that 38% of patients with morphea have associated genital LS strongly supports the fact that these 2 diseases share common pathogenetic pathways, and possibly a common genetic background, if they are not one and the same disease. Indeed, both entities are chronic inflammatory skin diseases characterized by dermal fibrosis. Lichen sclerosus could be the genital manifestation of morphea.

In conclusion, this study clearly shows that LS is significantly more frequent in patients with morphea. This finding should definitely affect our clinical practice. Indeed, it is not the standard of care to completely undress patients with morphea, and this practice is not recommended in the major dermatology textbooks.^24,26- 27Quiz Ref IDThe results of this study, however, show that it is mandatory to perform a complete examination, including the genital mucosa. That will allow us to diagnose a substantial number of cases of LS and eventually to prevent or at least to provide early diagnosis of the genital carcinomas that will arise on them.