Hodgkin lymphoma (HL) or Hodgkin lymphoma (as opposed to non-Hodgkin's lymphoma) is a type of lymphoma (cancer of the lymphatic system) characterized by the presence of large, atypical cells: Reed-Sternberg cells. The fact that this is the first well-characterized lymphoma led to call non-Hodgkin's lymphoma (NHL), by exclusion, all other types of lymphoma. Reed-Sternberg cell is essential for diagnosis, but it is not totally specific, and can be found (rarely) in other types of lymphoma (peripheral T lymphoma in particular).