DIAGNOSTIC-ACCURACY AND CHARGE-SAVINGS OF OUTPATIENT CORE NEEDLE-BIOPSY COMPARED WITH OPEN BIOPSY OF MUSCULOSKELETAL TUMORS

We performed a prospective study of sixty-two patients who were manage d with a closed core needle biopsy in an outpatient clinic for a soft- tissue mass or a bone turner with soft-tissue extension between August 1, 1992, and June 1, 1994. Eight (13 per cent) of the closed core nee dle biopsies yielded no neoplastic tissue. Two needle biopsies (3 per cent), which were of myxomatous masses, did not allow distinction betw een a benign and a malignant neoplasm; both masses were extraskeletal myxoid chondrosarcomas. Additionally, the histological grade of four r esected specimens (6 per cent) differed from that determined with the closed needle biopsy. The diagnostic accuracy of the closed needle bio psies was 84 per cent (fifty-two of sixty-two). All ten diagnostic err ors involved soft-tissue tumors. A retrospective study of a similar co hort of patients, who had open biopsy in an outpatient operating room by the same surgeon in a contemporary period in the same institution a nd with analysis by the same pathologist, revealed a diagnostic accura cy of 96 per cent (forty-eight of fifty). The hospital charges for the closed core needle biopsy were $1106, compared with $7234 for the ope n biopsy. We concluded that core needle biopsy can be performed in an outpatient clinic with use of local anesthesia and that it is substant iality less expensive and more convenient than open biopsy. This techn ique has an acceptable but definitely lower rate of accuracy compared with open biopsy, especially for soft-tissue tumors, and it should be used only in a small subset of patients (those who have a large soft-t issue mass or a bone tumor with palpable soft-tissue extension). Howev er, given the small size of the tissue sample, the clinician must reco gnize possible disadvantages, including a non-diagnostic biopsy, an in determinate biopsy, or a potential error in the histological grade. Th ese problems are much more likely to occur after core needle biopsy of soft-tissue masses. Because of the potential for errors in diagnosis when core needle biopsy is used, the musculoskeletal oncologist must r ely on his or her clinical acumen. When a diagnosis is in reasonable d oubt, there is no radiographic confirmation, the biopsy shows no tumor cells, or there is a combination of these findings, operative decisio ns should be made as if no biopsy had been performed. The management o f patients who, after core needle biopsy, have a diagnosis of a bone o r soft-tissue tumor, is best carried out by an experienced musculoskel etal oncologist working in close collaboration with an experienced mus culoskeletal pathologist.