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  • A Case of Eruptive Collagenoma on the Left Calf: DISCUSSION

Connective tissue nevi of the skin are acquired hamartomatous lesions consisting predominantly of one of the components of the extracellular matrix, namely collagen, elastin, or glycosaminoglycans. Among these, collagenomas are connective tissue nevi composed predominantly of collagen. They have been classified as either inherited or acquired. Inherited collagenomas include familial cutaneous collagenoma and Shagreen patch of tuberous sclero­sis. Acquired collagenomas contain isolated colla- genoma and eruptive collagenoma depending on the number of lesions but they cannot be differentiated clinically.

Eruptive collagenoma appears in the first or second decades as raised, cutaneous nodules or scattered papules on the trunk and arms. The lesions present as asymptomatic, skin-colored dome- shaped papules as well as nodules of various size but usually less than 1 cm in diameter. And there is no established family history or associated systemic findings.

Histopathologically the lesions are characterized by an excessive accumulation of dense, coarse collagen fibers in the dermis. Elastic fibers appear diminished in number, perhaps representing a dilu­tion phenomenon due to excess collagen accumulation. canadian pharmacy

Eruptive collagenoma should be differentiated from other diseases with focal absence of elastic fibers such as nevus anelasticus and papular elastorrhexis. Nevus anelasticus has been defined as acquired perifollicular papules with a paucity or lack of elastic tissue. Papular elastorrhexis is a variant of nevus anelasticus and it occurs in the twenties as multiple asymptomatic small, white papules scattered over the trunk and extremities with no predilection for the perifollicular areas. Nevus anelasticus and papular elastorrhexis show histologi- cally focal area of decreased and fragmented elastic fibers and most cases are sporadic but some familiar occurrence has been described. Some authors have mentioned these three entities represent a single disease or disease spectrum because of similar clinical and histopathologic features. They also have common features in terms of peak age of onset, distribution of lesion involving the trunk and upper extremities, and a lack of history of trauma, inflammation, family history, or extracutaneous manifestations.

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