The primary diagnosis of soft tissue tumours has emerged as an important new target for fine needle aspiration (FNA). The purpose of this book is to facilitate the cytological evaluation of FNA smears from soft tissue tumours and to suggest cytological criteria for histotype diagnoses. Its primary aim is to describe and illustrate not only the most common types but also those rare tumours where cytological features have been largely described in case reports and in small series. The diagnostic use of ancillary methods is discussed and illustrated, and, in order to facilitate the diagnostic work-up in FNA samples, smears are also classified according to their principal microscopic patterns. The selection of entities presented, their diagnostic features and differential diagnostic considerations are mainly based on the experience with FNA in the primary diagnosis of soft tissue tumours in patients referred to the Musculoskeletal Tumour Centre at the University Hospital in Lund, Sweden, over the last 30 years.