Soft tissue sarcomas: the usefulness and limitations of fine-needle aspiration biopsy.

The diagnosis of soft tissues sarcomas by fine-needle aspiration biopsy (FNAB) is controversial and relatively underused. We believe that the lack of acceptance by many clinicians and pathologists may be related to several factors. First, in comparison with other forms of cancer, soft tissue sarcomas are rare, constituting less than 1% of all malignant neoplasms. As a consequence, most pathologists lack extensive experience with the histopathologic and cytopathologic features of sarcomas. Furthermore, possibly no other subspecialty field of pathology is associated with a more bewildering spectrum of histomorphologic appearances. Because a diagnosis of malignant neoplasm may result in adverse consequences (eg, amputation), the pathologist involved with a soft tissue tumor diagnosis, especially with small biopsy specimens such as FNAB specimens, may be reluctant to give a specific diagnosis. Finally, of the pathologists with experience in the diagnosis of soft tissue sarcoma, many have been reluctant to endorse FNAB as a reliable procedure for establishing a definitive diagnosis. Nevertheless, FNAB among adequate specimens seems to have a diagnostic sensitivity and specificity of up to 95% for the determination of malignancy.False-positive and false-negative results approach approximately 4% (not including inadequate samples). If inadequate samples are included, false-negative rates may approach 10% to 15%. In this review, it is our intent to provide a comprehensive overview of the usefulness and limitations of FNAB in the diagnosis of soft tissue sarcomas, including a reappraisal of diagnostic criteria.