Fine needle aspirations typically use 22- to 25-gauge needles and several passes are made into the periphery of the tumor. There are several distinct advantages of fine needle aspiration over other biopsy methods. It is less costly, can be performed in the office without anesthetic, and an immediate answer can be secured during the patient’s office visit (Kaffenberger et al. 2010). Image guidance is not needed for FNA of palpable lesions that are safely away from vital underlying structures such as blood vessels but non-palpable lesions are better biopsied with image guidance. Either an ultrasound or a CT scanner can be used as the imaging modality of choice depending upon the expertise of the physician performing the biopsy. The main limitation of the fine needle aspiration is that it does not provide the evaluation of the tissue architecture (Fig. 3.2). A recently published study reported a diagnostic sensitivity and specificity of 89 % with fine needle aspiration (Ng et al. 2010). Other manuscripts have presented lower success rates with 79 % sensitivity and 72 % specificity (Kasraeian et al. 2010). These two studies demonstrate the most important rate-limiting step involved with the accuracy of FNA biopsy for musculoskeletal tumors, an expert cytopathologist. If there is no well-trained cytopathologist within the institution, utilization of fine needle aspiration biopsy is not a realistic option for diagnosis.

A second type of needle biopsy, called core needle biopsy, is slightly more invasive than a fine needle aspiration but can still be performed in the office without the need for surgical intervention (Adams et al. 2010). A 14-gauge needle is utilized. In this technique a local anesthetic is necessary. This additional needlestick minimally increases the risk of complication such as an allergic reaction. The costs of a core needle biopsy is slightly higher than FNA secondary to increased tissue handling needs that are required for its successful completion, but still much less than an open biopsy (Skrzynski et al. 1996). This biopsy technique can be performed either with or without image guidance depending upon the presence of a non-palpable or palpable mass. A recently published paper has also documented the sensitivity and specificity of this technique at 79 % and 82 % respectively (Kasraeian et al. 2010). Based on these success rates, a trained musculoskeletal pathologist, rather than a cytologist, is a minimum requirement and there is an additional cadre of pathologists that have been required to have the expertise to evaluate this type of specimen (Heslin et al. 1997).

Open biopsy is the gold standard technique as a study when diagnostic tissue for a bone lesion is required (Kasraeian et al. 2010). This procedure provides additional volume of the available specimen as well as a generally higher sensitivity and specificity with respect to diagnosis (Fig. 3.3). A representative sample is taken through the smallest possible longitudinal incision. It does have some downsides though; the risk of infection is higher, the cost is higher, and the risk of bleeding complications is increased. Additional bleeding within the wound bed can cause the possibility of further contamination by malignant cells. Any resultant hematoma should be considered contaminated and must be resected with the eventual definitive procedure. In addition, an open biopsy must be performed in an operating room using strict aseptic technique. The use of an operating room has additional costs as well. There are two types of open biopsy that can be performed. An excisional biopsy is performed by removing the entire tumor. An incisional biopsy removes a portion of the tumor to obtain diagnosis, and is the most common biopsy used for the diagnosis of bone sarcomas. It can be combined with frozen section analysis to ensure that diagnostic tissue has been obtained. It is generally accepted that the extraosseous component of the tumor is representative of the diagnosis and is adequate. Sampling of the intraosseous portion requires violation of the bone cortex and may pre-dispose the patient to pathologic fracture. This should only be done if there is no extraosseous portion. If the intraosseous portion requires sampling, the smallest corticotomy needed to gain diagnosis should be used.