Rita S:  Please explain the difference between high-grade and low-grade lymphoma.  Thank you.

Jose C. Villasboas Bisneto, MD:  Thank you for your question, Rita.  My name is JC Villaboas.  I’m a lymphoma doctor here at the Mayo Clinic in Rochester, Minnesota.  And your question regarding the difference between high-grade and low-grade lymphomas.  There are different ways to look at this question.  So, we can look at this question from a pathologist’s perspective.  So, pathologist being the doctor that looks under the microscope at biopsy results.  So, from a pathologist’s perspective typically, high-grade lymphomas are those that look more aggressive under the microscope compared to low-grade lymphomas that look less aggressive.  And typically, they can tell those two things apart by the shape and the size of the cells and how many cells they seem to be dividing compared to a low-grade lymphoma where the cells seem more quiet, more well-behaved, if you may.

However, most of the time when we’re discussing high-grade and low-grade lymphoma, we’re typically incorporating additional information beyond just the microscopy.  So that usually means that patients with high grade lymphoma typically will have a clinical course that is more aggressive compared to patients with low grade lymphoma, which tend to have a typical course that is less aggressive where the disease moves very slowly, which gives the body a chance to accommodate.  So if you imagine that if you have a tumor that’s growing very fast, that tends to push away structures, cause compression, symptoms, pains, while a cancer that grows slower gives the body a chance to find its way around it, accommodate.  So in many cases patients with low-grade lymphoma may have the disease for quite some time and not notice it until it becomes for one reason or another more obvious to the patient or the doctor taking care of them.  And then the other thing I like to explain patients regarding high grade and low grade lymphomas, you know, for more of a day-to-day perspective is typically high grade.  I tell patients these are the diseases that find the patient.

So, a patient is feeling well one day and then wake up with a symptom, whether it’s drenching night sweats or pain or a rapidly enlarging mass, such as in the case of lymphoma in the lymph node.  While low-grade lymphomas, I like to say that sometimes they are found by the patient in many situations by accident.  So, you go to the emergency room with a kidney stone and someone does a CT scan of your belly to look for kidney, the kidney structures, and they happen to find a few lymph nodes that are enlarged in the back of your abdomen.  You get a biopsy of those lymph nodes.  The lymph nodes are not the reason why you went to the emergency room, but you happen to find it while there, and that may lead to a diagnosis of lymphoma, commonly a low-grade, slow-growing type of lymphoma.

And then, one last piece about high grade versus low grade differentiation is in the specific case of follicular lymphomas.  So follicular lymphomas are the prototype indolent B cell non-hodgkin’s lymphoma which means that these are tumors, lymphomas of the B cell kind that tend to grow slowly therefore we use the term indolent but even inside the group of follicular lymphomas, we may have subgroups.  So, in the case of particularly follicular lymphoma, we have a differentiation between grade 1, grade 2, grade 3A, and 3B.  And we typically divide grades 1 and 2 as low grade and grades 3A and 3B as high-grade follicular lymphomas.  And we tend to treat the higher grades more aggressively as we would treat an aggressive lymphoma such as diffuse large B-cell lymphoma while in the case of grades one and two the low-grade follicular lymphoma that disease tends to be a lot more well-behaved and amenable to less aggressive treatment.  So, I hope that answers your question and thank you for having me here.