Types of Biopsy
- An excisional or surgical biopsy removes an entire lymph node for analysis, and is the most definitive way to diagnose non-Hodgkin lymphoma
- When an excisional biopsy may be difficult, needle biopsies can provide information
- A core needle biopsy removes only some cells from a lymph node; it can diagnose but not rule out non-Hodgkin lymphoma
- A fine needle aspiration uses an even smaller needle to remove even fewer cells; it can sometimes diagnose non-Hodgkin lymphoma, but cannot rule it out
Doctors will first do a physical exam and sometimes blood tests and CT or PET scans before they decide to investigate further for lymphoma. And depending on what they find, and where the swollen lymph nodes are located, they will do one of several types of biopsy.
Read MoreExcisional biopsiesalso called surgical biopsiesare considered the gold standard for diagnosing lymphoma. In an excisional biopsy an entire lymph node is removed for study. "It's the gold standard because lymphoma involvement of a lymph node may be patchy," explains Dr. Diefenbach. Meaning that unless an entire, affected lymph node is removed, it may not be possible to definitively rule out lymphoma. Excisional biopsies can often be done in the doctor's office, especially if the lymph node to be removed is right under the skin and easily accessible. In that case, the doctor simply injects some local anesthesia to numb the area, and then makes a small incision to remove the node. The node is sent to a laboratory for examination under the microscope to see if cancer cells are present. "If you have a lymph node excised and it doesn't show lymphoma, we can say with some confidence that whatever you have is probably not lymphoma," says Dr. Diefenbach.
But if the suspicious lymph node is located deep within the body, or in an area with a lot of blood vessels or nerves, then doctors may have to do a more involved surgical procedure. Sometimes patients even need to be placed under general anesthesia. In cases like this, doctors may decide to try a needle biopsy first to see if the diagnosis can be made that way.
Needle Biopsy
There are two types of needle biopsies: core needle biopsy and fine needle aspirate. Both can generally be performed as outpatient procedures in the doctor's office. And in both cases, only a portion of the lymph node is removed for study.
"In a core needle biopsy, a small needle is placed into a lymph node, and a few cells are taken out," says Dr. Diefinbach. If cancer cells are found when the sample is examined under a microscope, the doctor can diagnose non-Hodgkin lymphoma.
"However, because of the patchy involvement of the lymph nodes in non-Hodgkin lymphoma, a negative core needle biopsy may not be sufficient to rule lymphoma out," says Dr. Diefenbach. She says that if the doctor still suspects lymphoma after a negative core needle biopsy, "we'll need to biopsy you again or go in and remove a lymph node."
Another type of needle biopsy is called a fine needle aspirate. In this process, a tiny needle is inserted into a lymph node and a very small number of cells are extracted. "But because the needle is so tiny and the number of cells extracted are so small, we can't really learn about the cell architecture from this procedure," says Dr. Diefenbach. "If you're referred for a fine needle aspirate of a swollen lymph node and you're told it's negative, this in no way rules out lymphoma."
As with a core needle biopsy, a positive result can diagnose non-Hodgkin lymphoma . . but a negative result doesn't rule it out. If your doctor still strongly suspects non-Hodgkin lymphoma, you'll need to go for further testing, which may include a surgical/excisional biopsy.
Your doctor will decide what type of biopsy to recommend — and when — depending on your symptoms, results of other tests, and the location of the swollen or suspicious lymph node. Singly or together, these types of biopsy will provide the information your doctor needs to correctly make your diagnosis.
Reviewed by Dr. Sairah Ahmed, associate professor, Department of Lymphoma/Myeloma, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center
Reviewed by Dr. Sairah Ahmed, associate professor, Department of Lymphoma/Myeloma, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center
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