Lymphoma is a cancer that begins in the lymphatic system, which is an integral part of the body’s immune defense network. This disease develops when lymphocytes, a type of white blood cell, grow and multiply abnormally, often collecting in lymph nodes. Because the lymphatic system extends throughout the body, lymphoma can start in many different locations. Finding out you have lymphoma often involves a challenging diagnostic journey because the early signs can easily mimic symptoms of more common, less serious infections.
Initial Clues and Symptoms
The most frequent first sign noticed is a persistent, painless swelling of the lymph nodes. These lumps are commonly felt in the neck, the armpit, or the groin, where lymph node clusters are easily accessible beneath the skin. Unlike the tender, quickly resolving swelling that accompanies an infection, lymphoma-related enlargement typically remains present and may slowly grow over weeks or months.
Many people also experience a cluster of systemic symptoms referred to as “B symptoms.” These include drenching night sweats that soak clothing and bedding, unexplained fevers higher than 38°C (101°F), and an unexplained loss of more than ten percent of body weight over a six-month period.
Other, less specific symptoms that might prompt a visit include persistent fatigue that is not relieved by rest and generalized, severe itching of the skin without a visible rash. The combination of a newly palpable, non-tender lump and these systemic symptoms can raise the initial suspicion of lymphoma. Because these signs are not exclusive to cancer, they often lead to an initial search for infectious or inflammatory causes.
The location of the initial swelling can vary. Some lymphomas might start deeper in the chest or abdomen, leading to symptoms like a persistent cough or abdominal discomfort instead of a visible lump.
The Primary Care Evaluation
When a person first presents with suspicious symptoms, the primary care physician (PCP) begins the evaluation by gathering a detailed medical history and conducting a thorough physical examination. The physician checks all accessible lymph node areas—neck, armpits, and groin—to assess the size, consistency, and mobility of any swelling. They also palpate the abdomen to check for an enlarged spleen or liver.
To narrow the possibilities, the PCP typically orders initial laboratory tests, most commonly a Complete Blood Count (CBC) with differential, to check for abnormalities in blood cell counts. Blood tests may also include checking levels of lactate dehydrogenase (LDH), an enzyme sometimes elevated with high cancer cell turnover, and assessing liver and kidney function.
While these blood tests can sometimes show indirect signs of a problem, such as anemia or changes in lymphocyte counts, they cannot definitively diagnose lymphoma. The initial evaluation often includes a chest X-ray or an ultrasound of the swollen area to check for masses or deep lymph node involvement. These steps are designed to rule out infections like mononucleosis or tuberculosis before escalating to more specialized testing.
Confirming the Diagnosis
The definitive diagnosis of lymphoma cannot be established by symptoms or blood work alone; it requires a biopsy to examine the suspicious tissue directly. The preferred method is an excisional biopsy, where the entire suspicious lymph node is surgically removed. Removing the whole node is crucial because it allows the pathologist to study the complete architecture and structure of the tissue, which is essential for accurate classification.
A core needle biopsy, which removes a small cylinder of tissue, may be an alternative if the lymph node is difficult to access, but it provides less tissue for analysis. Fine-needle aspiration (FNA), which uses a very thin needle to withdraw only a few cells, is generally insufficient for a new lymphoma diagnosis because it does not preserve the tissue structure required for subtyping.
Once the tissue is obtained, a specialized pathologist examines it under a microscope to look for malignant cells. For Hodgkin Lymphoma, the pathologist searches for the characteristic large, abnormal Reed-Sternberg cells. If these cells are not present, the diagnosis falls under the Non-Hodgkin Lymphoma category.
The pathologist then performs ancillary tests, such as immunohistochemistry, which uses specialized stains to identify specific protein markers on the surface of the cancer cells. This detailed profiling confirms whether the cells are B-cells or T-cells and determines the specific subtype of lymphoma, a step that guides all subsequent treatment decisions.
Understanding the Lymphoma Types
The pathological analysis distinguishes between the two main categories of the disease: Hodgkin Lymphoma (HL) and Non-Hodgkin Lymphoma (NHL). This distinction is based entirely on the cellular appearance within the biopsy sample.
Hodgkin Lymphoma is defined by the presence of Reed-Sternberg cells. This type of lymphoma is less common, typically accounting for about ten percent of all cases.
Non-Hodgkin Lymphoma (NHL), by contrast, is a large and diverse group of cancers that lack these cells. This category includes over 60 different subtypes, which arise from various types of B-cells, T-cells, or natural killer cells.
NHL is significantly more prevalent than HL, representing the majority of all lymphoma diagnoses. The subtyping of NHL is important because the subtypes can range from slow-growing (indolent) forms that may not require immediate treatment to fast-growing (aggressive) forms that need urgent intervention.