- may be accomplished with a large needle or by open surgical methods;
- things to consider before biopsy:
- has the workup established metastatic dz (most common in patients over 40) vs isolated bone / soft tissue tumor vs infection (osteomyelitis);
- studies that may be performed prior to biopsy:
- MRI of lesion;
- CT scan of chest, abdomen, pelvis (assist with work up of metastatic disease);
- most common site of skeletal metastasis is the thoracic spine;
- bone scan;
- CBC, sed rate, CRP, blood cultures, Ca level, Chem 7, PSA, Alk Phos, UA.
- needle bx:
- involves less disturbance to tissue & is usually less extensive;
- where the soft tissue or bone lesion is accessible and near surface, needle biopsy is often a simple matter;
- when inserting the biopsy needle, it is essential that the pathologist be aware of respecting tissue planes,
- it is esp helpful technique when the diagnosis can be made on basis of a small number of cells, such as in metastatic cancer;
- two types of biopsies include: fine needle and core needle biopsies;
- fine needle biopsy:
- relies on cytologal interpretation by an experienced pathologist;
- its accuracy (65 to 95%) is determined in part by the adequacy of the collected tissue sample;
- it does not allow for immunohistochemical analysis;
- core needle biopsy:
- uses trocar cannula system, with a outer sleeve which closes over the trocar, capturing the sample of tissue;
- provides more tissue than fine needle and allows for immuno-histochemical analysis;
- accuracy ranges between 75 to 95%;
- disadvantages of needle bx:
- are that tissue obtained may be from necrotic portion of tumor and therefore not suitable for dx, or tissue may be reactive in nature and not
representative of actual tumor;
- Skrzynski MC, et al. (1996) recommend caution when a myxomatous tumor is diagnosed by needle biopsy, and recommend and recommend
an incisional biopsy for confirmation;
- Diagnostic accuracy and charge-savings of outpatient core needle biopsy compared with open biopsy of musculoskeletal tumors.
- Clinical Utility of Percutaneous Biopsies of Musculoskeletal Tumors.
- Needle biopsy of musculoskeletal lesions. A review of 208 procedures.
- Aspiration biopsy of primary neoplasms of bone.
- Diagnosis of eosinophilic granuloma of bone by cytology, histology, and electron microscopy of transcutaneous bone-aspiration biopsy.
- incisional open bx:
- where several areas of a tumor must be evaluated (as seen in cartilagenous lesions), larger sample obtained by open biopsy is to be preferred;
- incisional biopsies are performed (as opposed to excisional biopsies) inorder to minimize contamination of peripheral tissues and to preserve
the tumor's pseudocapsule (which facilitates future tumor excision);
- need for embolization:
- some lesions such as suspected renal or thyroid carcinoma should have preoperative embolization, but consideration should be given to embolization
if a non compressible lesion is present (such as might occur with a pelvic or acetabular lesions);
- surgical pitfalls:
- as a basic principal, the surgeon must be careful not contaminate tissue planes or compartments outside of the tumor's location;
- avoid mistake of placing a drain several cm away from incision site (may place tumor cells along the path of the drain;
- likewise transverse incisions will spread tumor cells across compartments;
- incision should go through a single muscle belly when possible (and avoid intermuscular planes);
- percutaneous biopsy should avoid crossing compartments, (ie biopsy of a distal femoral lesion through the suprapatellar pouch, or transversing
through an intermuscular septum;
- it is essential that hemostasis be obtained prior to wound closure;
- drains should be placed at either the proximal or distal end of a longitudinally placed incision;
- compression dressing is applied postoperatively
- Possible Metastasis of Osteosarcoma to a Remote Biopsy Site: A Case Report.
- Residual disease following unplanned excision of soft-tissue sarcoma of an extremity.
- Open surgical biopsy most accurate method for soft tissue mass diagnosis
- Considerations for Bone Biopsy:
- always contour smooth edges;
- make a circular or a longitudinal oval hole (torsional strength not affected by length of defect);
- attempt to keep defects less than 10% of bone diameter (maintains over 80% of bone strength);
- when biopsy size is greater than 20% of bone diameter, torsional strength decreases to 50%;
- The spread of tumor-cell-sized particles after bone biopsy.
- The effect of biopsy-hole shape and size on bone strength.
The hazards of the biopsy, revisited. Members of the Musculoskeletal Tumor Society.
THE CLASSIC: The Hazards of Biopsy in Patients with Malignant Primary Bone and Soft-Tissue Tumors.