Lymphoma is a type of cancer that begins in the lymphatic system. The lymphatic system is part of the body’s immune system and helps fight infections. There are two main types of lymphoma: Hodgkin lymphoma and non-Hodgkin lymphoma. Lymphoma can occur when lymphocytes, a type of white blood cell, begin to multiply uncontrollably.
What is Lymphoma?
Lymphoma occurs when white blood cells called lymphocytes grow out of control. Lymphocytes are a key part of the immune system and are found in lymph nodes and other lymphatic tissues throughout the body. There are two main types of lymphoma:
- Hodgkin lymphoma – Named after Dr. Thomas Hodgkin, who first described it in 1832. This type of lymphoma spreads in an orderly manner from one group of lymph nodes to the next.
- Non-Hodgkin lymphoma – A diverse group of lymphomas that account for around 90% of all lymphoma cases. The cancer cells can arise from B lymphocytes or T lymphocytes.
Both Hodgkin and non-Hodgkin lymphoma have many subtypes. Lymphoma can occur at any age but is most common in older adults. The causes are often unknown, but risk factors include:
- Weakened immune system
- Autoimmune diseases
- Family history of lymphoma
- Certain infections like HIV, Epstein-Barr virus, Helicobacter pylori
- Chemical exposures
Lymphoma often starts in the lymph nodes or lymphatic tissues like the tonsils and spleen. As the cancerous lymphocytes multiply, they can form tumors and spread to other parts of the lymphatic system and beyond.
Symptoms of Lymphoma
The symptoms of lymphoma depend on where the cancer is located. Common symptoms include:
- Swollen, painless lymph nodes in the neck, armpits or groin
- Fatigue
- Unexplained weight loss
- Fever and chills
- Night sweats
- Itchy skin
- Shortness of breath or cough
- Abdominal pain or swelling
- Feeling full after eating only a small amount
Some people with lymphoma do not have any symptoms initially. The cancer may be discovered incidentally during testing for other conditions. If lymphoma is suspected, tests and imaging will be done to confirm the diagnosis and determine the stage.
How is Lymphoma Diagnosed?
If lymphoma is suspected based on symptoms and physical exam, the doctor will order imaging and laboratory tests. These may include:
- Biopsy – Removing a lymph node or piece of tissue to examine under a microscope. This is the only way to definitively diagnose lymphoma.
- Blood tests – To look for abnormalities in blood cell counts and screen for infections.
- CT scan – Provides images of organs and tissues inside the body. Can detect swollen lymph nodes and tumors.
- PET scan – Uses a radioactive tracer to show areas of increased metabolic activity pointing to cancer.
- MRI scan – Provides detailed images using magnetic fields rather than x-rays.
- Bone marrow biopsy – Takes a sample of bone marrow to check for lymphoma cells.
These tests help determine the subtype and stage of lymphoma so the most appropriate treatment can be selected. The stage describes how far the cancer has spread and prognosis often depends on the stage at diagnosis.
Staging Lymphoma
Staging provides details on where the lymphoma is located and if it has spread beyond the lymphatic system. Hodgkin lymphoma is staged from I to IV:
- Stage I – Cancer is found in only one lymph node region or lymphatic organ like the spleen.
- Stage II – Cancer is in two or more lymph node regions on the same side of the diaphragm.
- Stage III – Cancer is in lymph node areas on both sides of the diaphragm.
- Stage IV – Cancer has spread to organs beyond the lymphatic system like the lungs, liver or bones.
Non-Hodgkin lymphoma may be described as:
- Localized (stages I and II) – Cancer is only in one part of the body like the lymph nodes in the neck or chest.
- Advanced (stages III and IV) – Cancer has spread to more than one part of the body or into the bloodstream.
Can Ultrasound Detect Lymphoma?
Ultrasound uses high-frequency sound waves to produce images of organs and tissues inside the body. It can help detect abnormalities in the lymph nodes that may indicate lymphoma. Lymphoma often causes lymph nodes to become enlarged as malignant lymphocytes multiply. Ultrasound can measure lymph node size and look for other suspicious features like:
- Irregular shape
- Abnormal texture
- Areas of necrosis or cysts
- Disrupted or missing fatty hilum
- Increased blood flow on Doppler ultrasound
Ultrasound has some advantages over other imaging modalities:
- No radiation exposure
- Wide availability
- Lower cost compared to CT or MRI
- Can assess lymph nodes throughout the body
- Can guide needle biopsies of suspicious lymph nodes
However, ultrasound cannot definitively diagnose lymphoma on its own. It can suggest lymph node abnormalities that may be due to lymphoma, but a biopsy is required for confirmation. Ultrasound is not as sensitive as CT or PET/CT for detecting subtle lymphoma involvement in normal-sized lymph nodes or other organs. It is limited in assessing lymph nodes deep in the abdomen or chest. Ultrasound is often used along with other tests as part of the lymphoma evaluation.
Neck Ultrasound
Swollen lymph nodes in the neck are a common symptom of lymphoma. Neck ultrasound uses a handheld transducer moved along the neck to view lymph nodes. This can detect:
- Enlarged cervical lymph nodes
- Changes in lymph node shape, hilum, and borders
- Abnormal blood flow on Doppler imaging
If abnormalities are seen, ultrasound can guide a needle biopsy of the lymph node for examination under the microscope. This is an easy way to obtain tissue for diagnosis.
Abdominal Ultrasound
The abdomen contains multiple lymph node groups as well as organs like the liver, spleen and kidneys that can be affected by lymphoma. Abdominal ultrasound uses a transducer moved over the abdomen to view:
- Enlarged lymph nodes near major vessels and organs
- Liver or spleen enlargement
- Kidney infiltration or obstruction
- Fluid accumulation suggesting nodal rupture or blocked ducts
Abdominal ultrasound may detect splenomegaly, hepatomegaly or retroperitoneal lymphadenopathy caused by lymphoma. Contrast-enhanced ultrasound uses microbubble contrast agents to better characterize lesions and blood flow.
Chest Ultrasound
Although CT is the mainstay for assessing the chest in lymphoma, ultrasound can also be useful. Endobronchial ultrasound with ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) allows sampling of hilar and mediastinal lymph nodes through the windpipe. Transthoracic ultrasound can also view the lungs, pleura, and mediastinum. Findings suspicious for lymphoma include:
- Enlarged mediastinal lymph nodes
- Lung lesions or nodules
- Pleural effusions
Scrotal Ultrasound
In males, lymphoma may spread to the testes and present as a scrotal mass or swelling. Scrotal ultrasound is the best imaging modality to evaluate testicular lesions. It can detect hypoechoic masses that could represent lymphoma infiltration of the testes.
Role of Ultrasound in Lymphoma Follow Up
Ultrasound may be used at intervals after lymphoma treatment to monitor response. It allows assessment of lymph nodes throughout the body easily and without radiation. Decrease in lymph node size on ultrasound indicates effective response to chemotherapy or radiation. Growing lymph nodes raise concern for persistent or recurrent disease. After treatment, CT scans are often done less frequently and ultrasound can provide interim surveillance imaging.
Ultrasound Limitations
While useful in the initial lymphoma evaluation and follow up, ultrasound does have some limitations including:
- Operator dependence – Results rely heavily on the skill and experience of the ultrasonographer.
- Difficulty assessing lymph nodes deep in the body, especially in obese patients.
- Can miss micrometastases in normal-appearing lymph nodes and organs.
- Not as sensitive as CT or PET/CT for detecting subtle disease.
- Limited field of view compared to whole-body modalities like CT and MRI.
- Image quality reduced by overlying bowel gas, body habitus, and surgical changes.
Ultrasound should not be used alone to stage lymphoma or monitor treatment response. Complete restaging with CT and/or PET/CT should follow abnormal ultrasound findings.
Should Ultrasound be Used to Screen for Lymphoma?
There are no recommended screening tests for lymphoma in people without symptoms or known risk factors. Testing can lead to false positive results, anxiety, and unnecessary follow up procedures. Ultrasound should not be used to screen the general population for lymphoma.
In certain high-risk groups like HIV patients and transplant recipients, ultrasound assessment of lymph nodes may be done at regular intervals along with blood work. This allows early detection and treatment if lymphoma develops in these immunocompromised patients.
Talking to your Doctor about Ultrasound
If your doctor suspects possible lymphoma based on clinical findings, ask about having an ultrasound for initial evaluation, especially of readily accessible lymph node groups. Ultrasound can provide additional information to guide next steps such as targeted biopsy or more advanced imaging. Use ultrasound to monitor nodes during and after treatment if you wish to limit radiation exposure from CT scans.
Understand that ultrasound has limitations in both diagnosing and following lymphoma. It should not take the place of tissue sampling or cross-sectional imaging modalities. Discuss how ultrasound will be integrated with other testing to fully assess your disease and response to therapy.
Conclusion
In summary, ultrasound can be a useful part of the lymphoma diagnostic workup and follow up care. It allows noninvasive assessment of enlarged lymph nodes throughout the body. Suspicious ultrasound findings can direct needle biopsy for diagnosis. Ultrasound can measure treatment response by tracking node size and changes over time. However, it has limitations in detecting subtle or deep lymph node disease. Ultrasound results must be correlated with clinical findings and more advanced imaging. While ultrasound may suggest lymph node abnormalities suspicious for lymphoma, a tissue biopsy is always needed to confirm the diagnosis.