Core Needle Biopsy

J. Taylor Whaley, MD
The Abramson Cancer Center of the University of Pennsylvania
Last Modified: December 15, 2014

What is a core needle biopsy?

  • A core needle biopsy involves the removal of tissue to better identify a lesion, or abnormality, felt on physical exam or seen on a radiology scan. Radiology tests are very good at finding abnormal things within the body; however, it is often difficult to know whether or not the abnormality is cancerous just based on how it looks. It is very important to remember that just because something appears abnormal, does not mean it is bad. The majority of abnormalities seen on radiology tests turn out to be benign (not cancer).
  • Frequently, abnormal masses are biopsied using the least invasive test, a Fine Needle Aspiration. The FNA procedure can obtain a collection of cells; however, it will not preserve the architecture, or structure, that the cells have within the body. A FNA can help your doctor know whether the abnormality contains normal cells, cancer cells or infection, but it is limited without knowing the surrounding structure. Because of this limitation, a core needle biopsy may be performed instead. A core needle biopsy provides significantly more information as it obtains much more tissue for the pathologist to evaluate.
  • You might ask why all biopsies do not begin with a core needle biopsy. For answers to this, please refer to Fine Needle Aspiration and Incisional & Excisional Biopsy for more details on those types of biopsies.
  • The core needle biopsy can be performed on most parts of the body. Common locations include the lymph nodes, breast masses, bone lesions, and the prostate.
  • Because a core needle biopsy is an outpatient procedure, minimally invasive, well tolerated, and quick, they are widely used.

How is this test performed?

  • A core needle biopsy is generally performed to follow up on an abnormality seen on a scan or found by physical exam. Core needle biopsies are performed as an outpatient procedure, under local anesthesia, or numbing medicine, without the need for general anesthesia.
  • While a FNA is performed with a very thin needle (even smaller than the needle used to draw blood), a core needle biopsy uses a slightly larger needle, similar to the needle used in drawing blood. This needle has a hollow middle, which can collect cells in their natural state, with surrounding cells attached. The needle is passed through the mass after the area is numbed with a local anesthetic. Generally, Lidocaine is the anesthetic most frequently used.
  • If the mass can be felt (palpated), the doctor can simply use an exam to guide the biopsy; however, if the lesion is too small or deep to be felt, a radiologist can use an ultrasound, x-ray, or the CT scan to help find the lesion.
  • The hollow needle is normally passed through the lesion several times to make sure enough tissue is obtained.
  • After the tissue is collected, the sample is placed onto a glass slide for a pathologist to examine. A pathologist is a doctor who specializes in looking at tissues under the microscope. After the pathologist has established a diagnosis, a report will be generated for your doctor.
  • The actual insertion of the needle is generally less than one minute. Again, it may be inserted several times to obtain enough of a sample. The whole procedure can take 15-30 minutes.
  • The most important risk associated with a core needle biopsy is bleeding. Generally, there is very little bleeding associated with the procedure, although rarely, a hematoma, or a pocket of blood, will collect at the site of the biopsy. This can be slightly uncomfortable but should resolve over the next few days. If there is severe pain following the procedure, you should contact your doctor immediately.

How do I prepare for a core needle biopsy?

  • Frequently, no preparation is needed; however, if you are on blood thinners, your doctor will likely have you stop them several days in advance. This should be discussed when the biopsy is scheduled.

How do I interpret the results of a pathology report?

  • Following the biopsy, the tissue sample is processed by a pathologist. A preliminary report may be given to the doctor; however, the final report generally takes several days.
  • The report generally states the patient's name, date of birth, site of biopsy, and indication (reason for the test) at the top of the report. Pathology reports follow a standard outline, regardless where they are obtained. The findings are discussed in a very systematic approach. For this reason, it is very important to discuss the results with your doctor.
    • The first paragraph typically reports the final diagnosis. This is a summary of the findings, often generated to answer the question posed by the ordering physician. If the biopsy is obtained for oncologic purposes, it commonly will state the findings are benign (not cancer), malignant (cancer), or unable to be determined.
    • The following paragraphs generally include the specific technical information involved in obtaining and processing of the sample. The details of the diagnosis can also be found here. Because reports are generated for other medical professionals, the terminology is often medically oriented and can be difficult to interpret.
    • You may want to ask for a copy of the report for your records, but you should ask your healthcare provider to review the results with you.


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