Leukemia vs. Lymphoma: The Differences Explained

The question of what the difference is between leukemia and lymphoma is a commonly asked question. We should start by saying that emerging research is demonstrating that, in reality, there is nothing that is different about these two diseases; rather, they are merely two different phases of the very same developing disease.

However, for the time being, we will consider them separate diseases and determine how and why that is.

Leukemia vs. Lymphoma

Both lymphoma and leukemia describe cancers that derive from blood-borne cells. This can mean lymphoblasts, lymphocytes, immunoblasts, plasma cells, and follicle center cells—in fact any blood-borne cells. And according to the American Joint Committee on Cancer (AJCC), at this stage of classification, there is no difference between lymphoma and leukemia; they are both now called lymphoid neoplasms (or lymphoid cancers).

Beyond Lymphoid Neoplasms

After the overreaching term 'lymphoid neoplasm', the next stage in classification is in terms of clinical presentation, and here is where the terms lymphoma and leukemia return and have some value:

Does the disease produce tissue masses (tumors) in the lymph nodes, or at extranodal sites? If so, it is a lymphoma.

Is the disease found only in circulating blood and not in form tissue masses? If so, it is a leukemia.

If the disease does both of these things, it is called a lymphoma/leukemia. Examples of this include small lymphocytic lymphoma and chronic lymphocytic leukemia are different phases of the same disease. The same is true for lymphoblastic lymphoma and acute lymphoblastic leukemia.

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