18-Year-Old College Cheerleader Diagnosed With Osteosarcoma After Dismissing Pain From ‘Overusing’ Her Knees

Mullooly, who admits a majority of her “determination” and positive outlook stems from her beloved sport of cheerleading, told The Patient Story, “On top of cheerleading practice, which I had twice a week in college, I would be going to the gym maybe three times a week, when I wasn’t in class … just always being active.

“I was doing legs one day at the gym, and I always get pretty sore from legs, but I noticed when a few days had passed, I was still very sore. I [then] noticed that my knee felt a little bit off. It wasn’t until a few weeks had passed that I was just still having on-and-off pain.”

What You Need to Know About Osteosarcoma

The American Cancer Society (ACS) explains how osteosarcoma, often called osteogenic sarcoma, is the most common cancer that begins in bone tissue. “The cancer cells in these tumors look like early forms of bone cells that normally help make new bone tissue, but the bone tissue in an osteosarcoma is not as strong as that in normal bones,” the ACS explains. Additionally, this type of sarcoma mostly occurs in children, teens and young adults, all ages can develop this disease.

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Noticing that the persistent pain in her knee lingered even while lying in bed weeks after it first started in the fall of her freshman year, Mullooly decided to see a doctor during her winter break at home in Long Island, New York.

She recalled her orthopedic doctor first doing an X-ray and concluding that she was “overworking” and “overusing” her knee, advising her to do physical therapy, thinking the issue wasn’t serious.

When the pain, which she thought was simply due to being “athletic” until her diagnosis, didn’t go away, she pushed for more answers and was sent for more testing, including an MRI.

Approximately an hour after the MRI, Mullooly received a call from her doctor while alone, prompting her to “panic” as she was told she had a tumor.

She continued, “When she told me it was osteosarcoma, in my mind I was like, ‘Oh this isn’t cancer?'” However, she then learned it was a type of cancer and her life was about to change.

Mullooly, who chose to save her eggs before treatment to have some “control” over her situation, also took to social media to share her story, telling her followers that she received her osteosarcoma diagnosis in March 2025.

The college student, who began her second round of chemotherapy in May, wrote on Instagram, “My world has been completely turned upside down all at an instant, but I’ve finally decided that I’m ready to share my journey.

“As hard and scary as it is to believe sometimes, I’m ready to fight and I know that I am strong enough to overcome this. In this new world of change and uncertainty that I now have to live in, all I can do is take things one day at a time.”

She continued, “The color yellow, symbolizing the ribbon used for sarcoma awareness as well as childhood cancer, now means a lot to me. It’s a symbol of optimism and sunshine to help me ground myself and channel positive energy as much as i can everyday, especially after already going through so much physically and mentally.

“All love and support is appreciated and I’m so grateful to have such amazing friends and family in my life through this difficult time for me. Please consider donating to my GoFundMe linked in my bio. Any amount is appreciated and will be a huge help. all funds will being going directly towards my medical treatments. thank you for supporting my journey against cancer.”

The GoFundMe, titled “Support Kelly’s Fight Against Cancer,” has since raised more than $65,000 from 657 donations, getting incredibly close to the $70,000 goal.

Mullooly, also a member of the Delta Phi Epsilon Sorority, has been doing well on her recovery journey and maintaining gratitude through it all, which she often takes to Instagram to share.

Uplifting news on a September 23 post on her GoFundMe also revealed, “We are excited to share a new update: After a recent follow-up with her surgeon, Kelly has been officially cleared to begin bearing weight on her leg (as tolerated) and to walk without crutches!”

The good news prompted the GoFundMe page to share the special milestone, showing Mullooly walking without crutches for the first time since her June 18th surgery.

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Then, on October 8th, Mullooly proudly announced that she attended the Sarcoma Foundation of America’s “Race to Cure Sarcoma” in New Jersey.

“I walked the full mile all by myself without any crutches, something I’ve dreamed of doing for months, and with my amazing team by my side,” she captioned her post.

“I’m proud of myself and I’m so grateful to have had the opportunity to represent the sarcoma community, walking for everyone impacted by this rare cancer. … My journey isn’t over yet, but it truly means the world to me to be supported by so many wonderful people.”

RELATED: A Cancer Survivor’s Ode To Friends and Family: “My Support System Helped Me Heal”

Mullooly admitted that she was scared prior to surgery but the trust in her doctors helped her power through adversity. Her surgeon was successfully able to remove the tumor, while sparing her leg.

She has since been going through chemotherapy and physical therapy. Mullooly also admits she may not be returning to cheerleading but she’s staying hopeful for the future.

Mullooly told The Patient Story, “The one thing I’ve taken away from this is that I get to help and inspire people.

“I’m now passionate in making people aware of what this is because obviously osteosarcoma is cancer, but no one would know what this cancer is unless it’s involved in your life.”

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All About Sarcoma Cancer

Sarcomas are cancers that develop in the cells responsible for supporting and connecting the body’s tissues. They can form in muscles, nerves, bones, fat, tendons, cartilage, and other types of connective tissue.

RELATED: What Are Sarcomas? Know the Types and Symptoms of These Rare Cancers 

“There are hundreds of different kinds of sarcomas, which come from different kinds of cells,” Dr. George Demetri, director of the Sarcoma and Bone Oncology Center at Dana-Farber Cancer Institute and Harvard Medical School, previously told SurvivorNet.

The word sarcoma refers to a large array of bone and soft tissue cancers; those are then further broken down into more specific forms of the disease, however, we will not list them all as there are more than 50 types of soft tissue sarcomas.

“Sarcomas are rare and the cause in most patients is unknown,” Dr. Vishal Gupta, site director of Radiation Oncology at The Blavatnik Family Chelsea Medical Center at Mount Sinai, previously told SurvivorNet.

The word sarcoma refers to a large array of bone and soft tissue cancers, and individual cancers within that set go by unique names. For instance, other types of sarcomas include:

• Ewing’s sarcoma is a cancer that typically occurs in and around the bones, often in the arms or legs, or the bones of the pelvis. It most commonly occurs in children and young adults.
• Kaposi sarcoma is a very rare type of cancer that causes lesions on the skin, in lymph nodes, organs, and the mucous membranes of the mouth, nose, and throat. It typically affects people with compromised immune systems, such as those with HIV.
• Epithelioid sarcoma is a type of soft tissue cancer that grows slowly. It is likely to begin under the skin of areas like the finger, hand, forearm, lower part of the leg, or foot.
• Synovial sarcoma, also called malignant synovioma, is a cancer that can form soft tissues such as muscle or ligaments, commonly close to joints or in areas like the arm, leg, or foot.
• Osteogenic sarcoma, also called osteosarcoma, starts in the bone, often as it is forming as a young person grows. This is the type of cancer Kelly Mullooly is battling
• Spindle cell sarcoma is very rare, comprising as little as 2 percent of all primary bone cancer cases. It can start in the bone, often in the arms, legs, and pelvis, and usually occurs in people over 40.
• Angiosarcoma: a rare cancer that develops in the inner lining of blood vessels and lymph vessels. It can occur anywhere in the body but is most often found in the skin, breast, liver and spleen.

WATCH: Bone Marrow Biopsy

Understanding the Signs & Symptom of Osteosarcoma

The typical symptom of sarcomas is a slow-growing, painless mass. But sarcoma can be hard to detect through symptoms. “Unfortunately, most sarcomas do not cause many of the symptoms that may be associated with other cancer,” Dr. Dale Shepard, director of the Cleveland Clinic Taussig Cancer Institute Phase I and Sarcoma Programs, told SurvivorNet in an earlier interview.

RELATED: High School Senior Who Married With Months To Live Puts Spotlight On Sarcoma ‘Forgotten Cancer’

Shepard explains that this often leads to large tumors at the time of diagnosis. “Soft tissue sarcomas are typically painless,” he says.

“Bone sarcomas may be mistaken for orthopedic injuries. A mass the size of a golf ball or larger and growing should be evaluated as a potential sarcoma. It’s important that patients who do have symptoms are not dismissive of them.”

Meanwhile, understanding the signs and symptoms of osteosarcoma, the type of sarcoma Mullooly is fighting, is crucial for early detection and effective treatment. While these symptoms can vary depending on the tumor’s size and location, there are common indicators to be aware of.

Key signs and symptoms of osteosarcoma may consist of:

• Pain: The most frequent symptom is pain in the affected bone, often described as a dull ache. It may initially be intermittent and worsen at night or with physical activity. Over time, the pain can become more constant.
• Swelling or Lump: Swelling or a noticeable lump may appear at the tumor site. This swelling can be variable, sometimes appearing weeks after the onset of pain.
• Bone Weakness and Fractures: Osteosarcoma can weaken the bone, making it more susceptible to fractures. These fractures can occur with minimal trauma or even during normal activities.
• Other Possible Symptoms: In some cases, there may be a limited range of motion in the nearby joints, especially if the tumor is near a joint. Weight loss and fatigue are less common but can occur, especially in more advanced stages.

Differentiating from Other Conditions:

It’s important to note that these symptoms are not exclusive to osteosarcoma and can be caused by other, more common conditions. However, persistent pain, swelling, or other changes in bone health should always be evaluated by a healthcare professional.

If these symptoms are present and osteosarcoma is suspected, the next step is a thorough diagnostic evaluation. This typically involves imaging tests and a biopsy to confirm the diagnosis. We will delve into the diagnostic process in the following section, providing a clear understanding of what to expect and how osteosarcoma is definitively diagnosed.

Carcinoma Vs. Sarcoma Explained

Dr. Gupta explains to SurvivorNet that the main difference between a sarcoma and a carcinoma is where they originate. “”A sarcoma typically occurs in soft/connective tissues of the body such as fat, muscle, blood vessels, bones, and nerves whereas a carcinoma typically occurs in organs such as the lung, prostate and breast.”

RELATED: New Hope for People with a Rare Type of Cancer Called Epithelioid Sarcoma

Or as Dr. Shepard puts it, a carcinoma comes from the cells that line organs (think lung, colon, or prostate), while a sarcoma comes from the cells that otherwise make up the organ: “Sarcomas are tumors in what people are made from after the organs are removed.”

Sarcomas may be treated by surgery, radiation therapy, and chemotherapy. Many patients benefit from treatment with more than one of these methods, Dr. Shepard explains.

Sarcoma Survivor Kara Ladd found solace in Reiki, Meditation, and Energy Healing During Treatment

“More than other types of cancer, the benefits of multidisciplinary care should prompt most patients to be seen by a group that specializes in treating sarcoma.” Dr. Shepard says.

“Even if only for a second opinion or to develop a treatment plan, multidisciplinary care is crucial. As examples, patients may benefit from surgical resection or radiation therapy even with metastatic disease. Patients may benefit from the addition of chemotherapy to radiation therapy prior to surgery to resect a sarcoma.”

Resilience Through Adversity & Overcoming Adversity

SurvivorNet specializes in covering the lives of people who overcome seemingly insurmountable obstacles, something Kelly Mullooly is doing. Often, seeing the positive helps them maintain their resilience.

Dr. Zuri Murrell, an oncologist at Cedars-Sinai Medical Center, spoke to SurvivorNet about the role of a positive outlook on survival rates: “I’m pretty good at telling what kind of patient are going to still have this attitude and probably going to live the longest, even with bad, bad disease. And those are patients who, they have gratitude in life.”

Meanwhile, resilience is an important trait, but not the easiest to build. When building resilience, the ultimate goal is not to avoid tough times, but to be able to bounce back from them. And yet, when they are faced with an overwhelming, life-changing situation, how do people shift their view? How do they learn to see the problem as temporary, rather than permanent, and figure out a solution?

It’s complicated, because building resilience is more about your mental and emotional fortitude than anything else. According to the American Psychological Association, “the resources and skills associated with more positive adaptation (i.e., greater resilience) can be cultivated and practiced.” In other words, resilience is not something you’re born with, which should be encouraging. Instead, after every challenge in your life, you build more and more resilience to those hard times.

Building resilience is down in the same way you build muscle, through patience and steady exercise of the skill.

Some lessons learned from other cancer warriors SurvivorNet has covered include being willing to learn, spending time with people who inspire you, allowing yourself to grieve, being flexible, and leaning in to your community for support.

Adversity And The Art of Happiness: How Hardship Makes You Even Stronger

Meanwhile, overcoming adversity can seem daunting. Many people think reciting upbeat mottos or pretending to be cheerful will help, but these solutions can make someone feel even more dejected than before. Instead, pay attention to the following steps to make meaningful change.

1. Set a goal. No matter what the situation, create a new goal for yourself. If you have just been diagnosed with cancer or a chronic illness, perhaps one goal would be to educate yourself about the disease and the possible treatments as much as possible.
2. Make a plan. How will you achieve this goal? Your plan will help you focus on that goal. Dr. Siddhartha Ganguly refers to this determined, focused mindset as “the eye of the tiger,” which can help people dealing with health problems, such as lymphoma and other cancers. “You have to have the eye of the tiger to go through this grueling process that is necessary these days to get rid of these virulent and aggressive cancers,” Dr. Ganguly, a cancer specialist at Houston Methodist, told SurvivorNet in an earlier interview.
3. Rely on others. Spend time with people who show you unconditional support and encouragement. They will alleviate your stress and help you remember that you’re not alone in this! Dr. Samantha Boardman, a psychiatrist and author, previously told SurvivorNet that one “coping strategy that can be productive is reaching out and talking to others. Having support we know is really critical in the healing process.”
4. Use positive self-talk. Leave messages with affirmations in places you frequent. Put notes around your mirror or the computer screen that say “You got this! or “Keep going!” Cut out inspirational quotes from people you admire and surround yourself with their words. Dr. Boardman explained to SurvivorNet that “Positive emotions have unique benefits above and beyond managing negative emotions.”

Facing Cancer: How to Turn Stress into Strength

If you’ve been through a difficult health challenge or any type of adversity throughout your live,  Dr. Boardman told SurvivorNet in an earlier interview that one way to get your mental health back in check after a diagnosis is to try to play up your strengths.

“I sometimes will ask patients, tell me about yourself when you were at your best,” she explained. “Using that story, trying to figure out what strengths come to mind. Is it patience? Is it appreciation of beauty? It is perseverance? [Then we can] use those strengths in constructive ways to navigate their cancer journey.”

Dr. Boardman says another way to approach harnessing the strength you already have is by tapping into your values. This could be family, close friendships, spirituality, or commitment to a healthy lifestyle.

Reminding yourself of what your values are and how you are living accordingly is another way to unleash that inner strength.

Advocating For Yourself While Navigating the Medical World

Contributing: SurvivorNet Staff

Learn more about SurvivorNet's rigorous medical review process.

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