A prospective study of the value of core needle biopsy and fine needle aspiration in the diagnosis of soft tissue masses.

We prospectively sampled 38 large soft tissue masses in 37 patients with both core needle biopsy (CNBX) and fine-needle aspiration (FNA) to determine the diagnostic utility of these biopsy methods. In 27 cases the histologic diagnosis made from the resected specimen was compared with the diagnosis based on the biopsy. CNBX correctly identified 16 of 16 malignant sarcomas and 10 of 11 benign masses (one was indeterminate). The grade of the sarcoma was determined correctly in every case. There were no false malignant or false benign CNBX diagnoses. FNA correctly classified 12 of 14 malignant sarcomas and four of 11 benign lesions. Diagnoses based on FNA were limited by a high proportion of samples, especially from benign lesions, that were inadequate for definitive diagnosis and by an inability to grade many malignant sarcomas. There were no significant complications resulting from the biopsies. We conclude that CNBX is a highly accurate, easily performed method for the diagnosis of large soft tissue masses that can be accomplished with minimal morbidity.