Lymphoid

Lymphoid is a term used to describe lymph or the lymphatic system.

In the context of lymphoid leukemia, it refers specifically to lymphocytes (which are the primary cellular component of lymph.) Lymphoid leukemias and lymphomas are now considered to be tumors of the same type of cell lineage. They are called "leukemia" when in the blood or marrow and "lymphoma" when in lymphatic tissue. They are grouped together under the name "lymphoid malignancy".

"Lymphoid tissues" contain lymphocytes, but they also contain other types of cells for support.

Lymphocytes and lymph vessels both derive from mesoderm, but from different lineages. Other parts of the lymphatic system, have other origins (the spleen derives from mesenchyme, and the thymus derives from the third pharyngeal pouch.)