CORE NEEDLE-BIOPSY FOR DIAGNOSIS OF EXTREMITY SOFT-TISSUE SARCOMA

Background: Classic teaching has advocated the use of open biopsy to d iagnose and grade extremity soft-tissue sarcoma. Reported advantages o f core needle biopsy include the minimal morbidity, cost, and time. Th e perceived disadvantage has been diagnostic inaccuracy. The objective of this study was to compare the diagnostic accuracy of core needle b iopsy to incisional or frozen section biopsy for primary extremity mas ses suspicious for soft-tissue sarcoma. Methods: Patients presenting w ith extremity masses were identified from our prospective soft-tissue sarcoma database (malignant) and from the clinical information center (benign) between January 1, 1990, and December 31, 1995. Biopsy and su bsequent resection data were collected from the pathologic records. Re sults: During this time, 164 primary extremity soft-tissue masses were evaluated before any biopsy. As the initial diagnostic approach, ther e were 60 core needle, 44 incisional, 36 frozen section, and 26 excisi onal biopsies. Two patients underwent two biopsy procedures. Ninety-th ree percent of the specimens obtained at core needle biopsy were adequ ate to make a diagnosis. Of the adequate core needle biopsy specimens, 95%, 88% and 75% correlated with the final resection diagnosis for ma lignancy, grade, and histologic subtype, respectively. Of the frozen s ection biopsy specimens, 94% were adequate, and accurate diagnostic re sults of malignancy were obtained with 88%. However, only 62% and 47% were correct for grade and histologic subtype, respectively, which was significantly different than the results obtained with incisional bio psy. The false-negative and false-positive rates for core needle biops y were 5% and 0% for malignancy. Two core needle biopsy specimens grad ed low were found to be high, and one core needle biopsy specimen grad ed high was subsequently found to be low on final resection. Conclusio ns: When read by an experienced pathologist, the results of core needl e biopsy provide accurate diagnostic information for malignancy and gr ade. Adequate core needle biopsy obviates the need for open biopsy and can be used for rational treatment planning. In the absence of adequa te tissue, open biopsy is required.