[Localised de novo dominant dystrophic epidermolysis bullosa]. / Epidermolyse bulleuse dystrophique localisée dominante de novo.

INTRODUCTION: Dystrophic epidermolysis bullosa is a hereditary heterogeneous blistering disease. Clinical examination and additional tests are not always sufficient to identify the subtype or mode of transmission. We describe a case of de novo dominant inherited dystrophic epidermolysis bullosa localised strictly to the knees. CASE REPORT: A 3-year-old boy presented symmetrical lesions on the anterior aspect of the knees since starting to walk. No nail, dental or mucous dystrophy was observed and the parents presented no clinical abnormalities. Optical microscopy, electron microscopy and immunofluorescence analysis suggested dystrophic epidermolysis bullosa. The genealogical tree allowed no distinction between the dominant de novo and mitis recessive forms. Genetic analysis identified a missense G 1776W mutation at exon 61 of gene COL 7A1 in the child's DNA but not the parents'. DISCUSSION: Dystrophic epidermolysis bullosa may present in generalized or localized forms and the disease may be inherited in either autosomal dominant or recessive mode. Genetic analysis shows mutations in COL 7A1. While the clinical features often allow different types to be distinguished when the parents do not have the disease (with the recessive forms being more severe), genetic analysis is essential to confirm the mode of inheritance. In the dominant forms, and more recently in recessive cases, glycine substitutions have been implicated, although the precise role of glycine substitution has yet to be clarified. Localised involvement of the skin alone, as seen in our case report, is very rare. CONCLUSION: Genetic analysis is important for genetic counselling and determination of risk of recurrence.

[Discrete papular mucinosis]. / Mucinose papuleuse cervico-céphalique.

BACKGROUND: Papular mucinosis is a rare dermatological disorder characterized by papules, nodules or plaques resulting from mucin deposits in the dermis, and to a certain degree, from fibrosis, without thyroid dysfunction. CASE REPORT: A 42-year-old man consulted for symmetrical papular lesions on the face, neck and shoulders. The lesions had gradually spread over some 20 years. Laboratory findings were normal. Histopathologic examination showed diffuse mucin deposits in the superficial and middle layers of the dermis, thick bands of collagen, proliferation of fibroblasts and mild perivascular infiltration by mononuclear cells. All of these findings pointed to a diagnosis of papular mucinosis. DISCUSSION: The specific interest of this case is the predominant involvement of the face and the spread of the lesions. According to the updated Rongioletti classification, this patient is presenting an atypical and novel form of papular mucinosis of a "mild papular" type with facial involvement. The 20-year history without systemic involvement or paraprotein suggests to us that this localized form will not develop into the systemic form or scleromyxoedema.