A Decade Without Answers: The Cancer Diagnosis That Changed Her Life for the Better

Misty Segrest spent more than a decade searching for answers as strange, painful bumps spread across her body. What began as a few small red dots on one finger multiplied. The rash crawled up her arms, around her neck, across her chest, and down her back. She said the itching was relentless.

"The welts felt like a million ants crawling across my skin," Segrest said.

Allergy medications offered little relief. Heat and sweat made her feel worse, and while her body was visibly reacting, Segrest said she felt nearly invisible to the medical system. She moved from specialist to specialist without a clear explanation.

"I felt ugly, ostracized, pushed out," she said. "Like a little bug that needed to be studied under a microscope by everyone I walked by."

Segrest's experience is common for patients living with systemic mastocytosis (SM), a rare disorder that occurs when mast cells, a type of white blood cell, accumulate throughout the body. The cells settle in tissues, especially those with external exposure, such as skin, lungs, and the gastrointestinal (GI) tract. When these cells become activated, they release tryptase and other mediators, which may trigger a range of symptoms such as skin rashes, GI distress, heart palpitations, fatigue, and even anaphylaxis.

"Patients don't present with one clear problem," said Tracy George, MD, ARUP Laboratories' chief scientific officer and president of the Innovation Business Unit. "They come in with a wide constellation of symptoms that cross many different specialties."

As a result, patients may see allergists, dermatologists, gastroenterologists, and cardiologists, and none of these specialists are looking at the full picture. Instead, George said, patients spend years being treated for individual symptoms rather than the underlying cause.

"On average, it takes nearly a decade for patients to receive an SM diagnosis," George said. "That's years of suffering, not being believed, and bouncing from specialist to specialist."

Segrest was eventually referred to the Huntsman Cancer Institute and Tsewang Tashi, MD, who ordered laboratory testing at ARUP, including a KIT D816V polymerase chain reaction (PCR) test and a serum tryptase test. Based on the results, Tashi diagnosed Segrest with indolent systemic mastocytosis, the most common and manageable form of the disease.

"For most people, a cancer diagnosis is a punch in the gut, but as long as the medication works for me, I can live a more normal life," Segrest said.

ARUP performs specialized laboratory testing for Huntsman and has developed highly sensitive tests for SM under the direction of George, who is a world-renowned expert in SM.

"Even when patients hear the word 'cancer,' there's often relief," George said. "Having an answer tells them they weren't imagining things, and most importantly, this is now a treatable condition."

George added that more than 95% of patients with SM carry the KIT D816V gene mutation, and the National Comprehensive Cancer Network (NCCN) recommends KIT mutational analysis as a first-line test for the evaluation of SM. KIT D816V mutation analysis can also be used to inform treatment decisions and monitor disease progression.

"If you know the exact mutation in a patient with systemic mastocytosis, you can then predict which therapy is going to work," George explained.

ARUP was the first large-scale clinical laboratory in the United States to offer a digital droplet polymerase chain reaction (ddPCR) test capable of detecting the KIT D816V mutation at low levels in peripheral blood, which helps clinicians determine whether more invasive testing, such as bone marrow analysis, is needed.

"If we can diagnose patients earlier, we can treat them earlier," George said. "And that can dramatically improve quality of life." George has dedicated her career to understanding SM and advancing care for patients with the condition.

"This has been my passion project," she said, reflecting on work that began early in her academic career; since then, she has been involved in every major clinical trial on SM. What motivates her most, she said, is the impact on patients' lives, seeing their symptoms fade and years of uncertainty finally give way to answers.

"Patients will tell you, 'My spots went away. I can exercise again. I can work. I can go out with my family.' That's why we're doctors," George said. "To help people who would otherwise have no one to help them."

George believes greater awareness among clinicians and patients is a critical next step. SM was once thought to be rare, but newer data suggest it may be more common than previously understood.

"It's now estimated that one in 5,000 individuals has systemic mastocytosis. That's not a rare disease anymore," George said.

Segrest said she wanted to share her story to encourage others experiencing symptoms not to give up. She credits an allergist and a dermatologist, who worked together, with determining that she needed specialized care and laboratory testing that ultimately gave her back her life.

"I cannot give enough gratitude," Segrest said as tears welled up in her eyes. "My life is so much better, and I don't feel like my skin is crawling all the time."

Join ARUP at the American Initiative in Mast Cell Diseases (AIM) Conference

ARUP is sponsoring the AIM 2026 Physician and Investigator Conference, May 16 and 17. View the ARUP experts' presentation schedule and details on poster presentations.

Bonnie Stray, [email protected]