A biopsy is the removal of a small amount of tissue under a microscope for examination. Other tests may indicate the presence of cancer but Hodgkin lymphoma can only be diagnosed after a biopsy of an infected tissue preferably by removing a lymph node.
The biopsy samples can be taken from an affected lymph node in the neck, under the arm, or in the groin. If there are no lymph nodes in such regions, it might be appropriate to have a biopsy of other lymph nodes, such as those in the chest core.
Usually this type of biopsy requires minor surgery under a procedure called mediastinoscopy. A thin, lighted tube is inserted into the chest by a small cut made just above the breastbone, with a camera and a cutting tool on the end. A biopsy may also be done using a core needle. Doctors use ultrasound or a computed tomography (CT) scan to help guide the needle to the correct location.
It is important that the sample taken for biopsy is large enough to allow the pathologist to make an exact diagnosis and to determine the Hodgkin lymphoma subtype. If there is not enough tissue in the first biopsy to diagnose lymphoma, then a second larger biopsy might be required. A cHL biopsy usually has Reed-Sternberg cells, as described in the Introduction. The Reed-Sternberg cells often look different for people with nodular lymphocyte-predominant Hodgkin lymphoma, and are called “LP” cells. Unlike typical Reed-Sternberg cells, LP cancer cells have a protein called CD20 on their surface.