Soft tissue tumours in childhood.

The spectrum of soft tissue tumours in young adults is very similar to that in more mature individuals, while those in childhood form a distinct group rarely seen outside the first decade. The majority of these are benign vascular or fibroblastic proliferations; in young children they may be highly cellular and mitotically active, but malignancy should be diagnosed with caution. Congenital soft tissue tumours constitute a special group in which the clinical outcome may be particularly difficult to predict from the histological appearances. This review focuses on those malignant soft tumours which are either peculiar to childhood or which manifest special features in childhood. Some recently recognized benign soft tissue tumours which occur mainly in childhood are also described. The fibromatoses are not discussed. As a guide to the appropriate treatment regime, the main histological distinctions to be drawn are between: 1 tumours of neuroectodermal origin (Ewing's sarcoma and primitive neuroectodermal tumour); 2 other sarcomas; and 3 the fibromatoses and other benign and potentially locally aggressive lesions requiring local excision. Immunohistochemical staining may be of considerable help in achieving the correct diagnosis, but it is vital that a panel of antibodies be applied and the results critically assessed. Cytogenetic analysis is also of growing importance, characteristic karyotypic abnormalities having been demonstrated in Ewing's sarcoma/primitive neuroectodermal tumour, alveolar rhabdomyosarcoma and synovial sarcoma.