Making the Diagnosis
There are two main goals when it comes to making an accurate tissue diagnosis of either breast lumps or abnormal spots on the mammogram. The first goal is to distinguish between benign tissue and malignant tissue. The second goal is to make certain that if a lump proves to be a cancer, the biopsy should have been done properly in order to facilitate future treatment planning.
There are some cases in which the diagnosis is almost certainly benign and the patient is anxious to have the lump removed. An example could be a young woman with a clinically benign mass (such as a fibroadenoma ). In such a case, it would be reasonable to remove the mass with an open excisional biopsy, and this avoids the cost and inconvenience of a two-step procedure. However, in the majority of lumps and suspicious spots on the mammogram, we do one of the following methods of tissue sampling, so that in the case of a malignancy, we can do appropriate pre-operative planning.
F.N.A. (or Fine Needle Aspiration)
A fine needle aspiration is simple office procedure that takes only a few minutes. A small gauge needle is placed in a breast lump/problem area, and cells from are extracted and placed on slide. The slide is sent directly to the pathologist. We typically use this technique when aspirating cysts or in evaluating lymph nodes in the axilla.
Core Needle Biopsies
Rather than just extracting cells (as with the fine needle aspiration), the core biopsy takes a sample of tissue. This small sample of tissue is usually sufficient to provide a specific tissue diagnosis. In other words, this procedure not only distinguishes between benign and malignant findings (as does the fine needle aspiration), it also usually defines a specific pathologic condition. For example, in the case of a benign condition, it might diagnose a fibroadenoma (see link), in which case nothing more needs to be done.
If the core biopsy states that the lesion of concern is malignant, it will typically differentiate between invasive or non-invasive cancer. It will also give information on the type of cancer present (i.e. ductal vs. lobular and high grade vs. low grade). In most cases, it will also allow for measurement of hormone receptors and other protein markers (link to understanding your path report)
Core needle biopsies can be used to diagnose large tumors without any form of guidance (i.e. free-hand, in which the surgeon inserts the needle by feeling where the tumor is). However in most cases, it is done with either ultrasound or x-ray guidance.
Ultrasound Guided Core Biopsy
If a lesion can be seen on ultrasound examination, we prefer to do an ultrasound guided core biopsy. This procedure is well-tolerated and is done with the patient lying comfortably on her back. A small titanium tissue marker is placed in the area of biopsy to show us where the biopsy was taken. The procedure usually takes only 10-15 mins and can be done under local anesthetic in the doctor’s office. Some post-biopsy bruising and tenderness can occur.
Stereotactic Core Biopsy
If a spot in question (usually calcifications) can only be seen on the mammogram, a stereotactic core biopsy is the procedure of choice (see diagram). In this procedure, the patient lies on her stomach and her breast protrudes though an opening on the table. The biopsy device is below the table. A core needle is directed to within a millimeter of the area. An aperture in the needle opens up and the tissue in question is sucked into the needle and removed. A small titanium tissue marker is placed in the area of biopsy, just in case all of the tissue and/or calcifications are removed and the lesion later proves to be malignant. The location of the tissue marker guides the treatment team to the area of the previously core biopsy, so that the entire malignancy can be removed.
Bleeding is the most common complication of this procedure. It is important that patients stop any medicines that can increase bleeding time (such as aspirin or other NSAIDs, coumadin, Plavix, etc.) at least 10 days in advance of the procedure. After the procedure, the patient is wrapped in a pressure dressing, which minimizes bruising. The procedure usually takes less than an hour.
Open Surgical Biopsy
In some cases, the core biopsy will be either non-diagnostic or may demonstrate the type of high-risk changes that require a more generous sampling of tissue. The decision to do an open surgical (or excisional) biopsy requires a coordinated discussion between the mammographer, the pathologist, the surgeon, and the patient.
In the case in which the area of concern is not palpable (i.e. not a lump that can be felt), a hook wire is placed before the surgical biopsy is performed. This is done in the radiology department under local anesthesia if the area cannot be visualized under ultrasound. If the tissue marker can be identified with ultrasound, the wire can be placed at the time of the biopsy by your surgeon. The wires allow the surgeon to locate this area based on the position of the wires. To make certain that the appropriate area has been removed, an x-ray is taken of the biopsy specimen after removal (while the wires are still present in the specimen).
In the case of a lump that the surgeon can feel, the open biopsy can be done without needle localization. In most of these cases, a needle biopsy is still done in advance so that an accurate diagnosis can be made.