Types of Biopsy
Several types of biopsy are used to diagnose Hodgkin's disease. Types of biopsy include the following:
- Fine needle aspiration (FNA) biopsy uses a very thin, hollow needle that is attached to a syringe. If the enlarged lymph node is palpable (can be felt) and near the skin's surface, the needle is inserted into the swollen lump. It is then pushed back and forth to free some cells, which are aspirated (drawn up) into the syringe and are smeared on a glass slide for analysis. If the suspicious nodes or tissues are deep within the body (e.g., abdominal nodes, thymus), the needle may be guided while it is viewed on a CT (computed tomography) scan. FNA can distinguish noncancerous conditions, like infections, from NHLs or other cancers. FNA also is useful for staging, or determining the extent, of disease, and for monitoring recurrence, or return of cancer. But, because of small sample sizes and lack of information about lymph node structure, FNA often is inadequate for the initial diagnosis of HD or NHL. In such cases, larger tissue samples are obtained by surgical biopsy.
- Large needle, or core biopsy, uses a large-bore needle to obtain a small tissue sample for analysis. Core biopsy has limited role in the diagnosis of lymphoma and is reserved for those patients who are unable to tolerate an invasive surgical procedure. Both FNA and core biopsy procedures may be guided by CT scan, ultrasound, or other imaging techniques.
- Surgical biopsy refers to both incisional (cutting into) and excisional (cutting away) procedures. If a tumor mass is large and only a tiny piece of it is removed for examination, the procedure is called an incisional biopsy. Incisional biopsy has, in large part, been replaced by needle biopsy; needle biopsy is less time-consuming and less prone to infection and it produces less scarring. If the tumor mass is small and it is completely removed by biopsy, the procedure is called an excisional biopsy. Excisional biopsy usually is performed if a physician suspects that a lump is not cancerous (benign). Local anesthesia is used if the node is located near the skin's surface and the child or adult is cooperative; however, deeper nodes (e.g., in the chest or abdomen) require general anesthesia.
Biopsy samples usually are sent to a laboratory for a number of additional tests, such as immunocytochemistry, flow cytometry, and cytogenetic studies. These tests, which also are used in diagnosing leukemia, rely on changes in cell-specific antibodies, the immune system chemicals that are directed against foreign substances, and genetic material to help identify specific types of lymphoma.