Pigmented skin neoplasm in a child: сomplex case report and review of the literature

Abstract

Introduction. Skin melanoma in children is a very rare disease that differs in many aspects from skin melanoma in adults. The conventional criteria for clinical diagnostics of melanoma observed in adults are often absent in children and adolescents, making it difficult to make a diagnosis on time.Objective. The aim of the study is to assess the clinical significance of various diagnostic criteria in the analysis of a rare case of congenital pigment skin neoplasm in a child.Materials and methods. The clinical case of a congenital melanocytic lesion in a wrist joint area in a girl 5 months old.During the primary diagnosis, an ultrasound examination was carried out. The tumor excision was performed with replacement of defect using moved skin flap. Histological, genetic and cytogenetic (fluorescent hybridization in situ, FISH) examination of a tumor sample was carried out.Results. The histological examination revealed areas of cellular atypia with high mitotic activity and the presence of pathological mitoses. According to FISH results, an increase in the copy of the RREB1 gene was observed in the sample, which may indicate amplification of this chromosome region. Genetic testing revealed a Q61K mutation in the NRAS gene.Conclusion. Despite the presence of histological features of neoplasm malignancy and ambiguous FISH results, the described case should be considered as congenital nevus with atypical proliferative nodes based on combination of clinical data (early age at the time of surgery, expansive growth pattern, multiplicity of nodes, lack of necrosis, long relapse-free period).