Navigating the unknown of uncommon cancers

When Arianne Missimer, a physical therapy doctor, nutritionist, and founder of the Pennsylvania-based integrated health center The Movement Paradigm, discovered a mass behind her right knee after experiencing nerve pain in her leg, she quickly planned an ultrasound.

“The pain didn’t really limit me,” says Missimer. “It was just an unusual symptom. If I hadn’t known my body that well, I could easily have ignored it. “

After the ultrasound confirmed the mass was solid, it was subjected to an MRI. The results were amazing. In March 2015, at the age of 34, Missimer was diagnosed with stage 3 liposarcoma, a rare type of cancer that develops in adipose tissue.

“I remember looking for ‘sarcoma’ and seeing that there are so many different types,” she says. “Then I looked for ‘liposarcoma’, but there wasn’t a lot of information out there.”

According to Dr. Melissa Burgess, a medical oncologist at UPMC Hillman Cancer Center in Pittsburgh, is not uncommon. “Unfortunately for some of these diseases there is no clear standard for the next step,” she explains. “There is a lack of data because it is a difficult disease to treat. It is also rare, so it is difficult to conduct large studies. “

“Sarcoma” is the collective term for a broad group of cancers of the bones and connective tissue. Of the approximately 1.9 million people who were diagnosed with cancer in the United States in 2020, Dr. Robert Maki, a medical oncologist and professor of medicine at the University of Pennsylvania, found only 17,000 – less than 1% – a sarcoma at Perelman School of Medicine in Philadelphia.

There are two general categories of sarcoma. Soft tissue sarcomas affect tissues that connect, support, or surround the organs and include sarcomas that are present in the muscles, tendons, fat, blood vessels, nerves, fibrous tissue, and synovial tissue. Bone sarcomas grow in the bone or cartilage. Between these two categories, sarcomas comprise 70 subtypes, which often makes accurate diagnosis difficult.

Brenda Kennedy, a yoga teacher and personal trainer in El Paso, Texas, experienced this difficulty after seeing the doctor about what she describes as a “dull toothache in the knee.” After an X-ray, bone, PET and MRI examination, a grade 2 chondrosarcoma was diagnosed in 2009 at the age of 31.

“But the most frustrating thing was how long the imaging took. I couldn’t get a referral to an orthopedic oncologist until everything else was ruled out, ”says Kennedy.


“In terms of frequency, about 3,000 people in the United States develop liposarcoma each year; with chondrosarcoma there are around 1,000 people a year, ”says Maki. “But the terms ‘liposarcoma’ (and) ‘chondrosarcoma’ also represent a family of tumors with other subtypes.”

Liposarcoma subtypes include well differentiated / dedifferentiated, myxoid / round cell, and pleomorphic. In chondrosarcoma, about 90% are conventional chondrosarcomas and the other 10% are subtypes that can be dedifferentiated, clear cell, mesenchymal, and myxoid.

Liposarcoma and chondrosarcoma are not only rare and, with their subtypes, highly specific, but also have few risk factors and often vague symptoms, which increases the difficulty and timeliness of the diagnosis. Maki points out that certain genetic syndromes, exposure to radiation to treat another type of cancer, exposure to certain chemicals, or a damaged lymphatic system can increase a person’s risk of sarcoma. With chondrosarcoma in particular, a family history of developing multiple benign cartilage tumors is a factor that could increase a person’s risk.

“We consider them to be unfortunate tumors,” explains Maki. “There is nothing that people did to get it. There is no connection with eating, drinking, smoking … nothing like that. “

“Over 80% of these cases are spontaneous,” emphasizes Burgess. “That is what makes it so challenging. We don’t know what is causing them, we can’t really study them, and they’re so rare. “

Both Missimer and Kennedy led healthy athletic lives prior to being diagnosed. Aside from the leg pain that took them both to the doctor, neither of them showed any serious symptoms.

“I remember getting so angry because I did everything right,” says Kennedy. “They say, ‘You have to eat right. You have to train. ‘ I’ve given fitness classes. … I did everything you were supposed to do and I was (still) dealing with a cancer diagnosis. “


Liposarcoma is most common in adults between the ages of 40 and 60 and shows up in the extremities (60%), abdomen (10%), and head and neck (10%). Chondrosarcoma, most common in adults between the ages of 30 and 70, can occur in any part of the skeleton. The type and severity of symptoms can vary greatly depending on where the tumor is located, as well as the stage and grade.

“Liposarcomas usually show up as painless lumps, like most cancers,” says Dr. Atrayee Basu-Mallick, director of the Multidisciplinary Bone and Sarcoma Center at the Sidney Kimmel Cancer Center. “That is why the diagnosis can be delayed at certain points – for example in the abdomen. Symptoms only occur when the tumor presses on another organ, nerve or blood vessel. “

Missimer’s punctiform nerve pain likely occurred as soon as the tumor got large enough to press against her sciatic nerve. She noticed it most when she sat down and crossed her legs. The majority of people may have a similar experience, but others may experience symptoms earlier.

Liposarcoma, for example in the head and neck area, usually causes a noticeable fullness; In the abdomen, there may be difficulty eating and using the toilet, as well as swelling or distension due to the growth of the tumor. As with most other cancers, it can appear with non-specific symptoms such as weight loss, chills, fever, fatigue, and night sweats. In some, the tumor shows no symptoms at all and is found by chance.

Chondrosarcoma symptoms, on the other hand, usually appear before a lump is noticed.

“(These) may include a feeling of pain, stiffness, and a change in the range of motion in the joints near the tumor growth,” explains Basu-Mallick. “If you have worsening symptoms, swelling, or a lump that you can feel, it’s always good to get this checked out.”


Basu-Mallick says the best treatment for each patient typically depends on five factors: the exact tumor type or histology, grade, stage, location, and the patient’s overall clinical picture, which is determined by other health issues.

“With sarcomas, the ‘grade’ is the most important factor in long-term prognosis,” she says.

The grade refers to how the tumor cells look under the microscope, while the stage refers to the tumor size and the local and distant spread. To determine the degree, factors such as the number of cells actively dividing, the number of cells that have died, and the general appearance of the cells compared to the primary tissue of origin are considered.

For example, for a Grade 1 tumor, a patient could be operated on to remove it. However, at Grades 2 and 3, treatment becomes more complicated – sometimes including a combination of chemotherapy and radiation – and the surgery is often expanded to remove areas around the tumor itself.

“Sarcomas are like a mountain of salt,” says Basu-Mallick. “The mound is the tumor, but there are small grains around it.

We have to get rid of this microscopic disease … so we have to remove a larger section to be on the safe side. “

When putting together a treatment plan, Burgess, Maki, and Basu-Mallick agree that a multidisciplinary approach is best.

“I always preach that it is helpful to have multiple doctors with different specialties review your case who can understand the disease and help create the plan,” says Burgess. “It is also very important to get to a center that has experience with sarcomas.”

At Kennedy, treatment involved removing six inches of her femur and placing a metal allograft. Over the course of five years, she underwent three other surgeries – including a total knee replacement, a megaprosthesis, and, due to her active lifestyle, repairing cracks in the polycarbonate structure. Since she had moved, Kennedy had surgery in a number of locations.

“Exercise and being outside have always been my way of relieving stress,” says Kennedy. “I was dealing with the most stressful thing in my entire life, and my only way to deal with it had been taken from me.”

Missimer, on the other hand, underwent fertility maintenance, six rounds of chemotherapy, radiation, proton therapy, and limb-preserving surgery that removed the tumor and part of her hamstring. “I felt really good, mentally, emotionally, and physically during proton therapy,” says Missimer, who began training for American Ninja Warrior, a sports entertainment competition based on tough obstacle courses while
still under treatment. “Then I had an operation and it was emotionally tough.”


Despite the complications that rare cancers like these can bring, health professionals are optimistic about the future.

“Since these tumors represent multiple types of cancer, there is an interest in breaking down each one and finding specific treatments,” explains Maki. “For example, half of regular chondrosarcomas have a mutation in a gene called IDH1 or IDH2 that hyperactivates the encoded enzyme isocitrate dehydrogenase, and there are now drugs that target these mutations. There is evidence of benefits for people receiving these drugs, although it is very early in the development of these drugs. “

Maki also notes a clinical study exploring another way to induce chondrosarcoma cell death without using chemotherapy.

“The big problem with chemotherapy for chondrosarcoma is that the chondrosarcoma is in the cartilage, where there are no blood vessels. You can’t just inject a drug into your veins and expect it to get to the tumor, ”he says. “But by using a monoclonal antibody that sticks in the body for weeks, you can get a drug in the body to kill these tumor cells.”

Although sarcomas are generally believed to be a type of cancer that is unresponsive to immunotherapy, oncologists including Burgess devote their time to studying specific genes expressed in the tumor and then identifying unique features within subtypes that respond to immune treatments.

Today both Missimer and Kennedy are cancer free. Kennedy’s fourth and final surgery was in March 2014, and she has maintained her active lifestyle by running three half-marathons, teaching yoga, camping, and keeping up with her four children. As for Missimer, she joined American Ninja Warrior three months after her surgery in May 2016.

“Physically I have limitations, but I was able to manage my pain and do my physical therapy, and I credit that to being as functional as I am,” says Kennedy. “I would tell patients to mentally prepare for pain; Prepare yourself mentally to keep up with physical therapy and be as active as possible to keep your body going. “

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