Tracy George, M.D.


Spotlight on SM Q&A with an expert pathologist and advocate for improving SM diagnosis

Tracy George M.D., a hematopathologist at the University of New Mexico School of Medicine with expertise in systemic mastocytosis (SM), discusses the challenges of diagnosing the disease and her advice for patients seeking a definitive diagnosis.

What drew you to the field of pathology, and how did you become interested in SM?

When I was an undergraduate at UC Berkeley, I wanted to be a scientist. Along the way, I met a pathologist, and learned that pathology was the study of disease and a subspecialty of medicine. I thought it was the perfect bridge between being a physician and being a scientist.

Years later, I became a faculty member at Stanford. With my team, I came upon a very different case altogether – a patient with mast cell leukemia. I became fascinated with mast cell disease. The more I learned, the more I wanted to learn. My colleague asked me if I would work with him on some projects on mastocytosis, and I said yes. That was over 13 years ago, and I’ve been working in this disease area ever since.

How frequently do you encounter patients with SM?

In my general practice, I encounter patients with SM a couple of times a year. It is a rare disease. However, my situation is a little bit unique: I am the pathologist on several clinical trials for advanced mast cell disease. As a result, I end up seeing a couple of those cases each month.

Over the years, I have developed a reputation as an expert, and so I get cases sent to me from around the country. I am part of a bone marrow working group, and we often exchange case information over email. Other pathologists often come to me for a second opinion because they just have not seen a lot of this disease. Or, they need help classifying the disease into a particular subtype.

As a pathologist, how do you collaborate with a medical treatment team to arrive at an SM diagnosis?

The treatment team for a patient with SM includes an oncologist or hematologist, as well as a nurse, who cares for the patient. Pathologists don’t typically speak with patients, but I do talk to their physician to understand symptoms.

Patients need to have a bone marrow biopsy in order for me to make a diagnosis; having information about symptoms is not quite enough. Once I receive tissue for examination, I have to perform special tests looking for mast cells and neoplastic mast cells. We’ll also perform flow cytometry on the blood to identify the mast cell count and the cells’ molecular composition. Finally, I look for mutations in the KIT gene. I need all of this information to make a diagnosis.

But it’s not enough in today’s world to say that you have mast cell disease. It must be classified as indolent or advanced. And if it is advanced, what type is it? In order to get that information, the pathologist has to collaborate with physicians because you need a lot of information to make these sub-classifications.

What challenges do clinicians face in diagnosing SM?

If you are not thinking about mast cell disease, you are not going to find it, because it is very uncommon. Most pathologists probably won’t have seen it more than once in their studies.

There are four challenges that make it difficult to diagnose SM:

  • First, you need an adequate tissue sample from a bone marrow biopsy, and that means enough tissue and making sure it has been properly prepared.
  • You also need to perform adequate testing. According to the World Health Organization (WHO) criteria,  you need to know whether there is a KIT mutation to diagnose SM. If you don’t look for the mutation, how do you know it exists?
  • Third, you need to be able to recognize mast cells. When you start having clusters of mast cells, that’s indicative of mast cell disease.
  • The final challenge is classifying subtypes of SM. This is very important because each subtype requires a different treatment. However, it’s such a rare disease that pathologists often do not have the training to do this.

Addressing these challenges requires education about the disease and bringing awareness of it to pathologists. Some of this is happening already. There are a number of online courses that have been developed for mast cell disease. Also, pathologists speak at conferences, and we have peer-reviewed journal articles; there are thousands of them about mastocytosis. I’m additionally introducing mast cell disease into my courses with residents.

What advice would you give to patients who suspect they have SM?

I think it is important for patients to educate themselves as much as possible about this disease and its subtypes. I always advocate for knowing whether or not you have a particular disease – it enables you to receive proper assessment and treatment.

Even though they don’t want bone marrow biopsies, patients should understand that a definitive diagnosis requires a bone marrow biopsy. So, I recommend that patients go to someone who does biopsies frequently and is good at it, which will make it a less difficult experience.

What is your biggest hope for patients who are searching for a diagnosis or who have been diagnosed with SM?

I want to ensure that people are properly diagnosed so that we can properly treat them. My hope is that we can develop drugs that will help patients with the disease and ensure that they have a long, happy and healthy life.

I want to ensure that people are properly diagnosed so that we can properly treat them. My hope is that we can develop drugs that will help patients with the disease and ensure that they have a long, happy and healthy life.

Tracy George, M.D.University of New Mexico School of Medicine