Lymphoma is essentially a cancer of Lymphocytes, a type of White Blood Cell (WBC). Leukemia is also a cancer of WBCs, sometimes involving lymphocytes, which begins while the cells are still immature, newly made in the bone marrow. Lymphomas usually begin once cells have matured and left the marrow.
Since lots of lymphocytes reside in our lymph nodes, that’s where Lymphomas commonly arise. There are many types and sub-types of Lymphoma, depending on the type of lymphocyte, and determined by a variety of features on biopsy. The broadest classification of Lymphomas are:
- Hodgkin’s Lymphoma (HL) (previously called Hodgkin’s Disease)
- Non-Hodgkin’s Lymphoma (NHL)
Both can involve a single main lymph node, or many (more common with NHL). Both can involve other organs (brain, stomach, skin, etc.), again more common with NHL. And both can be either aggressive; spreading and killing rapidly (especially NHL), or indolent (cause symptoms for quite a while before becoming aggressive).
Cancer in a lymph node can also be a metastasis from a cancer which originated in another part of the body. For example, throat cancer can first be noted by enlargement of lymph nodes in the neck; breast cancer can spread to nodes in the armpit; abdominal and genital cancers can spread through the main lymph duct to the node above the left collarbone. These are not lymphomas.
We suspect Lymphoma in two settings. One is when a lymph node has recently begun to enlarge (the medical term is lymphadenopathy). Infections cause lymph nodes to enlarge, but painfully. Nodes from cancer are almost always painless. They’re quite firm, maybe even hard; there may be others nearby. The key criterion for us is that it’s changing. Sometimes the node or nodes are internal, and we find them by chest x-ray, CT scans or other imaging. If advanced, we may note a large liver or spleen on physical exam.
We also suspect lymphoma when a patient simply hasn’t been feeling well, in fact, feeling a bit worse week by week, month by month. Fatigue is common. The key symptoms we ask about are called “B” Symptoms in medical jargon:
- drenching sweats
- weight loss
When these have been going on at least 2-3 weeks, and we don’t find abnormalities on physical exam or various blood tests, we’d order the imaging tests mentioned above. Obviously, many other diseases can cause these symptoms, including infections which also cause lymphadenopathy. Diagnosis is made by biopsy.
There are four types of biopsy: excisional (surgically removing an entire lymph node); incisional (removing part of it); core needle (aspirating a specimen through a large needle); or fine needle (a thin one). The latter is quickest and easiest, but may not retrieve an adequate specimen. For deep internal nodes, an “interventional radiologist” can manipulate a needle while doing a CT scan to get the sample. It’s important that an experienced pathologist perform the microscopic examination (often doing extra tests on the biopsy material as well). It’s also important for the patient not to have taken steroids if possible, since they obscure results.
The treatment and prognosis of Lymphoma depends entirely on the subtype, determined by biopsy. Some lymphomas can be cured, or controlled for a long time. Others resist therapy and advance rapidly. One complication of lymphoma treatment is that the chemotherapy and/or radiation used to cure the disease can itself cause a second cancer years later. It’s hard to know how to watch for this, except by investigating new symptoms, performing annual skin exams for skin cancers, and frequent mammograms.