DermPath

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Femme de 17 ans, présentant de multiples lésions de 2 à 10 mm, non indurées, blanc-jaunatres, des aiselles (photo), tronc, et cuisses.

Pas d'hyperkeratose, ou de bouchons folliculaires.

Biopsie au punch:

 

17 yo female with multiple, small (2–10 mm), nonindurated lesions, yellowish-white. There is no hyperkeratosis or follicular plugging.

Location: shoulders, chest, and thighs affected.

Punch biopsy:

 
     
     
     
       
     
  Bleu Alcian   Alcian Blue  
       
  Bleu Alcian      
 

Diagnostic proposé:

 

 

 

 

 

 

 

 

 

Sclérodermie en gouttes

 

Proposed diagnosis:

 

 

 

 

 

 

 

 

 

Guttate morphea

 
  Arguments: surlignés dans le texte ci-dessous   Clues: highligheted in the text below  
  Localized scleroderma in McKee's Pathology of the Skin, 4th Edition  
  In guttate morphea lesions are multiple, small (2–10 mm), nonindurated, and yellowish-white, and are limited by a delicate lilac border. Typically, there is no hyperkeratosis or follicular plugging. Coalescence of lesions to form plaques is not uncommon. Guttate morphea most commonly presents on the upper back and shoulders, but the lower back, chest, and abdomen may also be affected.There is much clinical (and histological) overlap between the lesions of guttate morphea and lichen sclerosus and it is worthy of note that the two disorders are frequently seen together.  
  The histological features of localized scleroderma involve both the dermis and subcutaneous fat; a deep incisional biopsy is therefore indicated if scleroderma is suspected. Biopsies from early lesions often show very subtle histological findings and are frequently non-specific. The histological diagnosis may be more difficult to establish in biopsies of lesions from guttate morphea as the changes tend to be more focal and superficial. In an established indurated plaque, the epidermis is usually normal or occasionally flattened. Mucin deposition is not usually a feature but may be occasionally present. Abundant mucin throughout the reticular dermis has been described exceptionally in nodular morphea. The papillary dermis either appears unaffected or shows a rather homogenized change. The most striking features are seen in the reticular dermis, where the collagen bundles are swollen, intensely eosinophilic, and orientated parallel to the surface. There is also involvement of the septa of the subcutaneous fat; this is associated with atrophy of the adipocytes and subsequent fibrosis, resulting in an apparent increase in thickness of the dermis. Hair follicles and sebaceous glands may be atrophic or absent and the eccrine ducts often appear compressed within the densely sclerotic dermis. Due to fibrous replacement of the subcutaneous fat, the eccrine glands appear to be situated abnormally high within the dermis rather than at the dermosubcuticular interface. In rare cases only the superficial reticular dermis is affected.  
  An important feature of localized scleroderma, especially in the early stages, is a dense, chronic inflammatory cell infiltrate of lymphocytes, histiocytes, and plasma cells; some authors believe this to be the initial feature. The infiltrate may surround blood vessels and appendages and tends to be particularly conspicuous in the dermis in addition to the subcutaneous fat. In the linear and generalized variants in particular, the inflammatory changes may affect the underlying skeletal muscle.  
  Differential diagnosis

The lesions of localized scleroderma may be histologically indistinguishable from those of systemic sclerosis, but the inflammatory cell infiltrate tends to be more pronounced in the former, at least in the early stages. Also, involvement of the papillary dermis may be a feature in some cases of localized scleroderma.

Other diseases that enter the differential diagnosis include late porphyria cutanea tarda and chronic GVHD. Adequate clinical information will resolve most diagnostic dilemmas, but where doubt exists, the presence of PAS-positive thickened dermal vessels is indicative of porphyria, whereas epidermal lichenoid features with cytoid body formation strongly support the diagnosis of chronic GVHD.

The relationship between localized scleroderma, particularly the guttate variety, and lichen sclerosus has been the source of considerable controversy. However, basal cell liquefactive degeneration with a lichenoid inflammatory cell infiltrate is not a feature of morphea, and sclerosis of the reticular dermis and subcutaneous fat with atrophy or loss of appendage structures is not seen in lichen sclerosus.