You don't know if this is a lipoma or not.. Most lipomas do not cause pain. You should know if this growth is under the skin, under the fascia, in muscle, between muscles or if it is something completely different. There are many malignant soft tissue tumors that could mimic the common lipoma. It would be prudent to get an MRI and get some information about it. If it is a typical lipoma it can be removed. But if there is anything suspicious about it, go to a regional center that specializes in soft tissue and bone tumor treatment for biopsy and treatment.The Hazards of the Biopsy, RevisitedFOR THE MEMBERS OF THE MUSCULOSKELETAL TUMOR SOCIETY*BY HENRY J. MANKIN, M.D.F, CAROLE J. MANKIN, M.S.L.S.T, AND MICHAEL A. SIMON, M.D.I, BOSTON, MASSACHUSETTSInvestigation performed at Massachusetts General Hospital, BostonABSTRACT: In 1982, members of the MusculoskeletalTumor Society, representing sixteen centers forthe treatment of bone and soft-tissue cancer, compileddata regarding the hazards associated with 329 biopsiesof primary malignant musculoskeletal sarcomas.The investigation showed troubling rates of errorsin diagnosis and technique, which resulted in complicationsand also adversely affected the care of thepatients. These data were quite different when thebiopsy had been carried out in a treatment centerrather than in a referring institution. On the basis ofthese observations, the Society made a series of recommendationsabout the technical aspects of the biopsyand stated that, whenever possible, the procedureshould be done in a treatment center rather than in areferring institution.In 1992, the Musculoskeletal Tumor Society decidedto perform a similar study to determine whetherthe rates of complications, errors, and deleterious effectsrelated to biopsy had changed. Twenty-five surgeonsfrom twenty-one institutions submitted the casesof 597 patients. The results were essentially the sameas those in the earlier study. The rate of diagnosticerror for the total series (in which cases from referringinstitutions and treatment centers were combined) was17.8 per cent. There was no significant difference inthe rate of patients for whom a problem with the biopsyforced the surgeon to carry out a different andoften more complex operation or to use adjunctiveirradiation or chemotherapy (19.3 per cent in the currentstudy, compared with 18 per cent in the previousone). There was also no significant difference in thepercentage of patients who had a change in the outcome,such as the need for a more complex resectionthat resulted in disability, loss of function, local recurrence,or death, attributable to problems related tothe biopsy (10.1 per cent in the current study, comparedwith 8.5 per cent in the 1982 study). Eighteen*No benefits in any form have been received or will be receivedfrom a commercial party related directly or indirectly to the subjectof this article. No funds were received in support of this study.tOrthopaedic Service GR606, Massachusetts General Hospital,Boston, Massachusetts 02114. Please address requests for reprints toDr. Mankin.tSection of Orthopaedic Surgery and Rehabilitation Medicine,Mail Code 3079, The University of Chicago Hospitals and Clinics,5841 South Maryland Avenue, Chicago, Illinois 60637.patients in the current study had an unnecessary amputationas a result of the biopsy, compared with fifteenin the previous study.Errors, complications, and changes in the course andoutcome were two to twelve times greater (p < 0.001)when the biopsy was done in a referring institution insteadof in a treatment center.The Musculoskeletal Tumor Society