Pediatria pre prax 4/2015

Nevi of skin in children. I. Pigmented nevi

Complicated structure of skin, compouded of different cells cause during ontogenesis formation of the variations in the development and deployment of what constitutes nevi. The name nevus comes from the Latin naevus, which generally refers to „birthmark or cosmetically troublesome character“. The name nevus is commonly used for colored marks, which are derived from the melanocytes, or the like cells. They are benign by their nature, are more aesthetic defect, although some may convert to malignant cancer. Nevi also participate in many syndromes. According to origin cells participating in their construction nevi are distinguished on epidermal nevi – derived from keratinocytes, which may also be with hairs and sebaceous glands (organoid nevi). Hair follicles form naevus pilus often in conjunction with melanocytic nevus. The sebaceous glands create an independent naevus sebaceus. Connective tissue nevi are derived from fibroblasts and fat tissue nevi are derived from adipocytes. Vascular nevi are derived from vascular components. The most frequently are occurred melanocytic nevi from melanocytes and nevomelanocytes – pigmented nevi. Pigmented melanocytic nevi create spectrum of manifestations from accumulation of few melanocytes in the epidermis, to massive accumulation melanocytes and nevomelanocytes in the corium. Melanocytic nevi are divided into melanocytic hyperplasia and melanocytic neoplasia. The causes of nevi are not fully known. They are considered as specific mutations (B-BRAF) or the clonal nature of progeritors cells created nevi and some others conditions (UV). This heterogeneous group of disorders is most recently allocated on the basis of clinical and histological features as follows. Neoplasia include: congenital nevomelanocytic nevus, nevus spilus, acquired nevocelular nevus, blue nevus, pigmented spindle cell nevus, Spitz nevus, nodal nevus. Hyperplasia include: lentigo simplex and solar lentigo. Special group consists of: dysplastic nevus, freckles, spots type of café au lait, Mongolian spots. There are described a clinic diagnosis, treatment and prevention of pigmented nevi and is emphasized the need for education of children and parents in what the pediatricians have the main role.

Keywords: nevi, children, clinical findings, treatment, prevention.