Lymphoma carcinoma is a tricky term and might, to the knowing reader, seem either contradictory or at least somewhat repetitive. First let's discuss what the main cancer tumor terms mean:
Sarcoma
A sarcoma is any cancer that develops in connective tissue in the body. This could be:
-- Bones
-- Nerves
-- Muscles
-- Tendons
-- Blood
Carcinoma
A carcinoma is any cancer that develops on the surfaces of places in the body. This could be:
-- Kidneys
-- Lungs
-- Skin
-- Other organs
BUT Wait! If doctors attach the ending –oma, it means the cancer is benign. If they attach sarcoma or carcinoma it means it is malignant. Osteosarcoma is a malignant bone cancer, or renal cell carcinoma, or carcinoma of the lungs.
Wouldn't then the term "lymphoma" mean that lymphomas were benign? After all, we have the lymph—where the cancer began—and the benign ending --oma. Unfortunately, because lymph cells travel in lymph fluid they are connective tissue, and are technically lymphosarcomas. Leukemia gets tied in with lymphoma to create lymphoid cancers—these are cancers of the blood cells.
The answer is—that there is no such thing as a lymphoma carcinoma. At least as its own disease. A person or an animal may have a lymphoma AND a carcinoma, but how these two terms got tangled up, I don't know. But it's very easy to do a search for lymphoma carcinoma as a single term and find several hits, but what happens when you click through to them? Confusion.
Because a cancer is either developing in cells that are lining organs, in stuff that connects those organs to each other, or in the blood cells that form deep in our bone marrow. Science will pretty much find a way to categorize any cancer according to whether it's a sarcoma, a carcinoma, or a lymphoma.
Finally, the last rule to remember is that once you think you know the rules, the rules change. Cancer research is like cancer itself—always changing.