Fine-needle aspiration cytology of soft tissue lesions: diagnostic challenges

Clinical and radiographic data provide important information in the evaluation of soft tissue lesions/neoplasms. Morphologic tissue and cytologic examination is considered to be a necessary part of the diagnostic work-up. The standard procedure for obtaining tumor tissue for morphologic evaluation has been incisional (open) or core needle biopsy. An increasing use of minimally invasive diagnostic procedures has resulted in better acceptance of fine-needle aspiration cytology (FNAC) in the diagnosis of soft tissue lesions. This article discusses challenges in FNAC of soft tissue lesions based on the experience at a multidisciplinary referral sarcoma center. Obtaining sufficient specimens from deeply seated small and necrotic/cystic lesions is technically a potential pitfall and misdiagnosis of cells from reactive zones surrounding the tumor as well as the correct evaluation of spindle cell lesions, rare soft tissue neoplasms, and "new entities" lacking reproducible cytological criteria are other important challenges in FNAC of soft tissues. The successful cytological evaluation of soft tissue lesions requires the application of strict, reproducible morphological criteria in the context of the clinical findings as well as ancillary techniques. The minimal criteria for diagnostic intervention in various clinical settings and the relative advantages and disadvantages of FNAC must be understood. FNAC of soft tissue lesions is facilitated when limited to specialized orthopedic-oncologic centers with a well-integrated multidisciplinary team and experience in the evaluation and therapy of soft tissue lesions.