5 - Adipocytic Tumors

Abstract

Adipocytic tumors represent the commonest group of mesenchymal lesions and the category of Adipocytic tumors includes several entities, all sharing variable features of lipomatous differentiation. These lesions, which can occur at every age and at almost any anatomical location, are part of the daily practice of every surgical pathologist. While the vast majority represent commonly encountered tumor types (e.g. benign lipoma), the heterogeneity and rarity of other adipocytic neoplasms can pose diagnostic challenges. Atypical and malignant adipocytic tumors account for approximately 20% of all sarcomas. The awareness of the existence of the various clinicopathologic entities, and of their main characteristics, is essential to avoid diagnostic pitfalls. The classification of adipocytic tumors has evolved significantly over the past several decades, thanks to a better biological understanding, with substantial contributions from cytogenetics, molecular genetics, and immunohistochemical correlates.