differential (a test in which the relative percentages of each type of blood cell are determined) ■ Erythrocyte (red blood cell) sedimentation rate (ESR) test ■ Comprehensive metabolic panel to check liver and kidney function ■ Testing for infection with the human immunodeficiency virus (HIV) and hepatitis B and C viruses ■ Positron emission tomography (PET) and computed tomography (CT) scans What Is a Biopsy? A biopsy is a procedure in which a piece of tissue from an area of suspected disease is removed from the body and examined under a microscope. The information provided by this tissue sample is crucial to correctly diagnose the disease and to decide on the best course of treatment. Table 3.1 on the next two pages shows the three main types of biopsies used in patients with suspected HL. Questions to Ask Before Having a Diagnostic Procedure (continued) ■ How will the results of this test affect my treatment? ■ Will my insurance cover the procedure? ■ What will my out-of-pocket costs be? ■ If I will be receiving a dye, are my kidneys healthy enough to handle it? 25 Understanding Hodgkin Lymphoma Table 3.1. The Three Main Types of Biopsies Excisional or Incisional Biopsy ■ This type of biopsy is generally considered the best to establish an initial diagnosis of HL because it allows the removal of bigger samples than other biopsy procedures. The larger the sample, the more tissue can be examined, which improves the accuracy of the diagnosis. ■ A surgeon cuts through the skin to remove an entire lymph node (excisional biopsy) or a large portion of a lymph node or other tissue (incisional biopsy). ■ If the lymph node is close to the skin surface, the procedure can be done under local anesthesia to numb the area. If the lymph node is in the chest or abdomen, the patient is sedated and the surgeon removes the tissue either laparoscopically (through a tube inserted in the body) or by performing more extensive surgery. Core Needle Biopsy ■ This procedure is used when the lymph nodes being examined are deep in the chest or abdomen or in other locations that are difficult to reach with excisional biopsy, or when there are medical reasons for avoiding an excisional or incisional biopsy. ■ A large needle is inserted into the lymph node and a small tissue sample is withdrawn using a syringe attached to the needle. This can be done under local anesthesia, and stitches are usually not required. ■ Sometimes the material collected may not be adequate for diagnosis, so a subsequent excisional or incisional biopsy may be necessary. ■ Often the core needle biopsy is guided by an imaging test, such as an ultrasound, CT scan, or PET scan. Learning the Basics 26 Part 1 Table 3.1. The Three Main Types of Biopsies (continued) After a tissue sample has been removed, it is examined by a pathologist (doctor who specializes in the diagnosis of diseases by studying the cells from a patient’s body fluids and tissue samples). A hematopathologist (pathologist who has undergone additional training in the diagnosis of blood diseases, including lymphoma) may also examine the sample. These specialists identify and classify the lymphoma cells by looking at their shape and size and how they are grouped in the sample. An oncologist (doctor who specializes in treating patients with cancer) or hematologist (doctor who specializes in treating patients with blood cancers and other blood disorders) uses the pathologist’s report, along with results of other diagnostic tests, to confirm a diagnosis. A pathologic diagnosis and accurate classification of specific lymphoma types can sometimes be difficult to make. If the pathologist’s interpretation of the biopsy is uncertain, the biopsy should be reviewed by an expert hematopathologist. Biopsies that are interpreted as “normal” may still contain HL cells. This may occur when the sample is small and therefore not representative of the rest of the lymph node. Sometimes a repeat biopsy is needed to establish the diagnosis. It takes an experienced hematopathologist working with the hematologist or oncologist to determine the need for more tissue sampling. Fine Needle Aspirate (FNA) Biopsy ■ This procedure is performed with a very thin needle that is smaller than the kind