Diagnosis
If a child has symptoms of lymphoma, a doctor should take his or her medical history and conduct a physical exam to determine what might be causing them. During the physical exam, a doctor should thoroughly examine the lymph nodes. The doctor should also ask if there have been any sweats, weight loss, or unexplained fevers. If the doctor notices any abnormal or swollen lymph nodes, he or she should look for any signs of an infection that may be causing them. If the doctor suspects lymphoma, he or she may conduct a lymph node biopsy to be certain. Here are some of the procedures the doctor may recommend to diagnose lymphoma:
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Needle Biopsy
A doctor may first request a “fine needle aspiration” or a “core needle biopsy” to evaluate the reason for an abnormality he or she finds on a physical examination or X-ray. In general, though, biopsy must be done. In both procedures, a doctor, often a radiologist, may use a CT scan or an ultrasound, a machine that uses sound waves to create a picture of the node or abnormal tissue, to guide a needle to an abnormal lymph node and extract a tissue sample. The doctor will send this sample to a pathologist who will examine it under a microscope and make a diagnosis based on what the cells look like as well as cell-surface markers that support the diagnosis. If material removed from the patient is not adequate or not completely clear and the doctor still suspects lymphoma, he or she will most likely recommend an excisional biopsy. After diagnosis, the doctor may recommend additional biopsies to check for cancer spread to other parts of the body.
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Surgical Biopsy
If the doctor highly suspects lymphoma, he will usually recommend that a surgeon remove either an entire swollen lymph node (excisional biopsy) or a small piece of it (incisional biopsy) and have it sent to a lab to be examined under a microscope for signs of lymphoma. A pathologist will examine the size, shape, and arrangement of the cells in the tissue sample to identify the specific type of lymphoma. An excisional biopsy is the standard of care. It is the most reliable method of diagnosing this disease and is very important, although an incisional biopsy can be enough in cases where the node is very large.
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Bone Marrow Aspiration & Biopsy
In this test, the doctor uses a thin needle to extract a sample of tissue from the hip bone and has it sent to a lab to be examined under a microscope. This procedure is not often used to diagnose lymphoma, but can help determine if the cancer has spread to the bone marrow and establish the stage of the disease.
Immunophenotyping
Diagnosing lymphoma can be difficult and sometimes examination of the cells under a microscope is not enough to provide a definitive diagnosis. The pathologist may use special stains to identify certain proteins found in different types of lymphomas to help classify the lymphoma, and to establish what type it may be. Genetic testing of the tumor cells may also be very helpful.
Blood tests
The doctor may recommend blood tests such as a complete blood count (CBC) to determine the levels of different cells in the blood, or a blood chemistry test to monitor protein and electrolyte levels, and liver and kidney function. These tests are not used to diagnose the disease, but can help detect problems caused by abnormal cells and organ involvement and are also useful in monitoring the side effects of therapy.
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Echocardiogram
Certain chemotherapy drugs commonly used to treat Hodgkin lymphoma can cause heart damage on the long term. An echocardiogram is an ultrasound of the heart. Ultrasounds bounce sound waves off of your internal organs in order to create echoes that form a picture. The doctor may obtain regular echocardiograms while on these medications to monitor the size and function of the heart.
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Pulmonary Function Test (PFT)
Certain chemotherapy drugs used to treat lymphomas can cause damage to the lungs. PFTs measure how efficiently lungs inhale air and distribute oxygen to the bloodstream. The technician gives the patient a mouthpiece connected to a machine that measures exhaled gases, and asks the patient to breathe in as deeply as possible and exhale for as long as possible. The doctor may recommend regular PFTs while on medications to monitor lung function.
Chest X-Ray
X-rays use electromagnetic radiation to produce images of the inside of the body. The doctor may order a chest X-ray to see whether the cancer has spread to the lungs, or to evaluate the size of nodes in the chest (mediastinum).
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Computed Tomography (CT) Scan
A computed tomography (CT) scan uses X-rays to produce an image of your body. A special dye may be injected into your veins and you may be asked to drink a special fluid in order to make the internal organs stand out. A CT scan reveals the presence of tumors and whether or not the cancer has spread to other parts of your body. After treatment is finished, doctors have found that lymph nodes often have some leftover tissue that can be seen on this type of scan. Studies have shown that often these leftover findings are nothing but scar tissue, and are not active cancer.
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Magnetic resonance imaging (MRI) scan
Magnetic resonance imaging (MRI) uses radio waves and a strong magnet to create clear and detailed images of body parts. Radio waves are absorbed by the body and then released in a certain pattern, which is translated by a computer in order to show “slices” of the body. MRI's can evaluate the brain and spinal cord, although these are very rare sites of involvement in lymphomas.
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Positron emission tomography (PET) scan
For a PET scan, the doctor injects a radioactive substance into the patient's bloodstream. This substance collects in malignant (cancerous) cells in the patient's body. The doctor then uses a PET scanner to detect these areas of radioactivity and to find the exact location of cancer in the patient's body. The PET images can be fused to a CT scan for improved detail. Studies have shown that PET scans are often better than CT scans at finding lymphoma. Also, after finishing treatment for lymphoma doctors will often want the PET scan to show no signs of the disease, especially in cases where the CT scan still shows enlargement of nodes or possible scar tissue.
