Long‐lasting follow‐up favours a close relationship between progressive facial hemiatrophy and scleroderma en coup de sabre*

The study on the differentiation of scleroderma en coup de sabre (SCS) and progressive facial hemiatrophy (PFH) by the Mexican group, with the distinguished researcher R. Ruiz-Maldonaldo, in the field of collagen diseases merits special attention.1 The authors of this study found that the differentiation between these disease entities is in most cases possible based on clinical assessment and histological findings. They studied patients of the National Institute of Paediatrics in Mexico City in the 20-year period from 1978 to 1998. Thirteen patients were diagnosed with SCS and nine recognized as PFH. The consensus diagnosis showed a remarkable concordance between dermatologists and pathologists. In eight of 13 SCS cases there was cutaneous sclerosis, which was not present in the PFH cases in which more frequent features were total hemiatrophy and ocular changes. Connective tissue fibrosis and adnexal atrophy were found significantly more frequent in PFH, whereas mononuclear cell infiltrates were present in all cases of SCS and in only six of nine PFH. This very careful study, with evaluation based on well-defined clinical and histological criteria, has disclosed important differences between the two groups studied. We had a very similar experience, and we reported differential–diagnostic criteria as a basis for objective diagnosis.2,3 However, in over 20 years of follow-up of 71 patients with PFH (56 children and 15 young adults), we found that the morphological pattern changed progressively. The primarily sclerotic lesions with diagnostic features of SCS became atrophic, similar to or identical to idiopathic hemiatrophy not preceded by skin indurations. The characteristic clinical features and histological pattern of localized scleroderma disappeared progressively, sometimes with traces of deeper sclerosis or fibrosis in subcutis. We found both conditions overlapping, and the coexistence of PFH and scleroderma on the trunk or extremities in 37% of patients in the younger age group and in 20% of the older age group.4,5 Because the histology was also of no help in the differential diagnosis we tried various noninvasive techniques. Ultrasonography in our hands had limited use, showing only the size and depth of atrophies, and did not contribute to differentiation between the diseases. Using various techniques, we performed a study in 19 cases of PFH classified into two groups: the first with atrophies preceded by cutaneous indurations, and the second with atrophies not preceded by indurations.6 Seven cases of SCS served as control. The techniques used were: magnetic resonance imaging (MRI) before and after contrast application to evaluate the integrity of the blood–brain barrier; angio-MRI to evaluate intracranial blood vessel anomalies; and single photon emission computerized tomography (SPECT) to evaluate regional cerebral blood flow. We disclosed similar abnormalities in a considerable number of patients in all three groups. The SPECT technique, applied for the first time in a relatively large series of patients with PFH and SCS, disclosed a significant decrease in regional blood flow, also found in patients with normal morphological findings in MRI.6 Thus SPECT might be a very useful technique allowing for recognition circulatory cerebral disturbances at the level of microcirculation. In our SCS series, SPECT showed in some cases functional abnormalities, while the morphology, as disclosed by MRI, was normal. Taken together, the studies performed with the use of noninvasive techniques have not provided criteria for differentiation of PFH and SCS, and did not show any differences between the cases of PFH either preceded or not preceded by indurations. Both PFH and SCS appear to be heterogeneous neurocutaneous syndromes, and idiopathic PFH not preceded by sclerotic lesions is in essence a deep primary atrophic localized scleroderma, not preceded by visible sclerotic changes. Such deep primary atrophies are occasionally seen on the extremities. Irrespective of how such cases would be classified, the most important is involvement of the central nervous system (CNS) in both SCS and PFH. In addition, the ocular involvement noted by the authors was found to be identical in SCS and PFH.7,8 The neurological disturbances depend mainly upon the degree of CNS disturbance. However, in about 10% of patients with PFH, pronounced anomalies are due to a cerebral defect of congenital origin producing both cerebral dysgenesis and hemiatrophy.9,10 These cases should be classified as a special subtype, whereas the majority of PFH cases have a close relationship with scleroderma and appear to belong to the spectrum of scleroderma.