Final answer:
Non-Hodgkin lymphoma (NHL) is the type of lymphoma most likely to involve extra nodal sites. It has different subtypes that affect immune system cells called B cells or T cells. Lymphoma can spread from the lymph nodes to other organs.
Step-by-step explanation:
The type of lymphoma most likely to involve extra nodal sites is non-Hodgkin lymphoma (NHL). NHL has many subtypes, depending on factors such as which specific cells are affected. Some subtypes of NHL affect immune system cells called B cells, while others affect immune system cells called T cells. Lymphoma can spread from the lymph nodes to other organs, including extra nodal sites, such as the respiratory and digestive tracts.