HISTOLOGICAL DIAGNOSIS IN PEDIATRIC DERMATOLOGY

The histological diagnosis is important for paediatric as well as general dermatology; it is valuable in diagnosing excised tumors or skin malformations, and for the differential diagnosis of skin biopsies from many dermatoses. A prerequisite for the reliable histological examination of biopsies is the knowledge of its indications, the selection of a relevant skin lesion, and an adequate biopsy technique. Fixation and pretreatment of the excised tissue have to correspond to the scheduled histological techniques (paraffin embedding and routine staining or special methods). The histological differential diagnosis of melanocytic nevi and melanomas, other skin tumors, genodermatoses (ichthyoses, epidermolyses), acquired bullous diseases, and different exanthemas are mentioned as examples. Sometimes, the histological sections may present surprising features, e.g. fungi or a scabies mite in the cornified layer of the epidermis. Apart from avoidable technical mistakes, there are some limitations especially in the histological diagnosis of inflammatory exanthemas which require additional laboratory methods.