Pathology of Soft Tissue Sarcomas

Sarcomas are a rare, complex group of childhood and adult neoplasms with differentiation towards mesenchymal tissue, which may arise almost anywhere in the body. Although pathologically diverse, they frequently exhibit similar clinical presentations and radiological features. Correct histopathological diagnosis is therefore crucial, but there is overlap between histological patterns of malignant tumours, between benign and malignant lesions, and with non-mesenchymal tumours. Immunohistochemistry and molecular genetic techniques, the latter to detect tumour-specific alterations, add significantly to histological interpretation, but several groups of tumours still lack reliable immunohistochemical markers or reproducible genetic changes. The classification of sarcomas is incomplete and continues to evolve, and although the biology of many remains relatively poorly understood, our increasing insight into molecular events occurring in these tumours is certain to aid future diagnosis and therapy. This paper aims to give a broad overview of several of the main soft tissue sarcomas from a clinicopathological perspective, discussing laboratory diagnosis and the use and limitations of ancillary investigations, including recent developments in molecular diagnosis.