Lymph nodes are small, bean-shaped structures that function as filtering centers within the lymphatic system, an integral part of the body’s immune defense. They contain specialized white blood cells, called lymphocytes, which trap and neutralize foreign invaders like bacteria and viruses. Finding a lump or swelling in the neck, armpit, or groin is common and often signals the body is fighting a routine infection. While most swollen nodes are benign and resolve on their own, any persistent or unusual lump warrants attention from a healthcare provider.
Physical Characteristics of Lymphoma-Related Lumps
The texture and feel of an enlarged lymph node offer clues, but they cannot definitively diagnose the cause of swelling. Lymphoma-related lymph nodes are often described as having a characteristic firm or “rubbery” consistency when felt under the skin. This texture results from the uncontrolled accumulation of abnormal lymphocytes within the node. They feel distinct from the surrounding tissue but are not necessarily rock-hard, which is sometimes associated with other types of metastatic cancer.
A key differentiating feature is the presence or absence of pain. Lymphoma-related swelling is typically painless, meaning the lump does not hurt when touched or pressed. Conversely, a lymph node swollen due to an active infection is usually tender, painful, and warm to the touch, indicating an acute inflammatory response. This tenderness results from the rapid fluid build-up and inflammation as immune cells mobilize to fight a pathogen.
The mobility of the lump when palpated is another physical characteristic examined. Lymphoma nodes are frequently described as being movable or mobile under the skin when pressure is applied. However, as the disease progresses, or in certain types of lymphoma, the nodes can become fixed or matted together, feeling less movable or tethered to deeper tissues. A node is considered enlarged and concerning if it measures greater than 1.5 centimeters in diameter.
Common Reasons Why Lymph Nodes Swell
The most frequent reason for lymph node enlargement, known as lymphadenopathy, is a benign, temporary response to infection. When a person has a common cold, the flu, a throat infection, or a dental issue, nearby lymph nodes swell as part of the normal immune process. This reactionary swelling is caused by the rapid proliferation of white blood cells and the accumulation of fluid as the body filters and destroys pathogens. Once the infection is cleared, the inflammation subsides, and the nodes typically return to their normal size within a few weeks.
Swelling caused by lymphoma arises from a fundamentally different biological mechanism. Lymphoma is a cancer of the lymphatic system, involving the uncontrolled growth and division of abnormal lymphocytes. These cancerous cells multiply excessively and collect within the lymph node, causing pathological enlargement. Unlike an infectious cause, this growth is autonomous and does not rely on an external pathogen to trigger swelling.
Because the underlying cause is persistent cellular proliferation rather than a temporary immune reaction, nodes swollen due to lymphoma do not shrink back down once a supposed infection has passed. The medical distinction is between hyperplastic nodes, which are reactive to infection, and neoplastic nodes, which are enlarged due to cancerous cell growth. Other conditions, including autoimmune disorders or benign growths like cysts and lipomas, can also cause lumps that may resemble swollen lymph nodes.
Typical Locations for Lymphoma-Related Swelling
Lymph nodes are distributed throughout the body, but only those close to the skin’s surface are easily felt as lumps. The most common areas where lymphoma-related swelling is first noticed are the cervical region (neck), the axillary region (armpit), and the inguinal region (groin). These superficial nodes are often the first to swell because they drain lymph fluid from the head, limbs, and lower torso. Swelling in these locations is readily observable and often prompts an initial medical evaluation.
Lymphoma can also affect nodes deeper within the body, which are not accessible to physical examination. These internal nodes include those in the chest cavity (specifically the mediastinum), the abdomen, and the pelvis. Swelling in these areas may cause other symptoms by pressing on nearby organs, such as a cough or shortness of breath if the nodes press on the trachea or lungs. An enlarged spleen or liver, which are also part of the lymphatic system, can be a sign of internal lymphoma involvement.
The pattern of swelling can offer additional context, as lymphoma can cause multiple nodes to swell in one area or in several non-contiguous areas. Some types of lymphoma can also originate outside of the lymph nodes entirely, in organs such as the skin or bone marrow. However, the presence of an unexplained, persistent lump in the neck, armpit, or groin remains the most common physical presentation.
When to Consult a Healthcare Provider and Next Steps
Any lump that develops under the skin and persists without an identifiable cause should be evaluated by a healthcare provider. A concerning sign is a swollen lymph node that does not decrease in size within two to four weeks, or one that continues to grow larger. Nodes that are painless, firm, or rubbery, especially those larger than 1.5 centimeters, also raise suspicion and warrant prompt medical attention.
The presence of constitutional or systemic symptoms alongside the lump increases the need for evaluation. These are collectively known as B symptoms.
B Symptoms
These symptoms include unexplained fevers that come and go over several weeks, drenching night sweats that soak clothing and bedding, and unexplained weight loss. Weight loss is defined as losing 10% or more of total body weight over six months without trying.
The first steps a healthcare provider will take involve a detailed physical examination and a review of the patient’s medical history. They will assess the size, texture, and mobility of any palpable lumps and check for signs of infection. If lymphoma is suspected, the provider may order blood tests, such as a complete blood count, to check for abnormalities in blood cell levels. Imaging scans, such as an ultrasound, CT scan, or PET scan, may also be ordered to visualize nodes deep within the body and assess the extent of the enlargement.
The definitive diagnosis of lymphoma requires a biopsy, where a sample of the enlarged lymph node is surgically removed and examined by a pathologist. An excisional biopsy, which removes the entire node, is often preferred because it provides the most tissue for accurate testing and classification of the specific lymphoma type. This procedure is the only way to confirm the presence of cancerous lymphocytes and determine the best course of treatment.