Undifferentiated Tumors:

Undifferentiated, A Definition (1)

A term used to describe cells or tissues that do not have specialized (“mature”) structures or functions. Undifferentiated cancer cells often grow and spread quickly.

This is a somewhat scientific post. Keep reading because it’s very interesting.

Tumor grade is different than cancer stage.

After the doctor biopsies, suspicious tissue, he or she sends it to a pathologist. The pathologist then determines whether the tissue is malignant. Furthermore, they can tell what kind of cancer it is, as well as what the tumor’s stage is. Your doctor may also ask the pathologist to also check for specific mutations which can be treated using targeted treatments.

When a pathologist looks at the cancerous tissue under a microscope, they assign a tumor grade. This is based on how similar the tumor cells and the tissue are to normal, healthy cells. They call tumor cells that are more like healthy cells, “well differentiated.” They call more abnormal the cells, “undifferentiated.” This is important because, in undifferentiated cancer, the cells are immature. In addition, undifferentiated tumors are likely to grow and spread quickly.

Making the Grade

There are several ways to grade tumors, This is a popular method. Pathologists give tumors a grade of 1, 2, 3, or 4. The lower the number is, the more normal the cells and the organization of the tumor appears. Grade 3 and 4 tumors grow rapidly, dividing and spreading faster than tumors in grades 1 and 2. (2)

  • GX: Grade cannot be assessed (undetermined grade)
  • G1: Well differentiated (low grade)
  • G2: Moderately differentiated (intermediate grade)
  • G3: Poorly differentiated (high grade)
  • G4: Undifferentiated (high grade)

It’s important for doctors to know a patient’s health history, the stage of their cancer, and the tumor grade to determine a patient’s prognosis and put together a treatment plan.

Sinonasal undifferentiated carcinoma – high magnification By Nephron – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=21382293

To Know or Not to Know

Patients sometimes get upset that their doctor has given them a poor prognosis based on the cancer being advanced and their tumor(s) being undifferentiated. You can tell your doctor at the outset, how much information you are comfortable hearing about your cancer. Tell your doctor if you don’t wish to be given certain details about your cancer. They will usually take care to honor that. Doctors base these predictions on statistics as well as their years of experience. Still, they are statistics. A patient is not a statistic. At the same time, a prognosis can be extremely valuable in making treatment decisions as well as end of life planning.

Our Story

Early on, we saw the word, “undifferentiated” on countless reports over the past four and a half years. What did it mean? Undifferentiated almost sounds okay. It sounds like it’s not clear, so maybe it’s not that serious. We found out how wrong we were in November of 2015 when Dan began to have a hard time breathing. He coughed whenever he tried to talk or take a deep breath, due to undifferentiated cancer filling his lungs. Radiologists call this “ground glass,” because it looks like ground glass on scans.

I have a picture of one CT scan that shows the comparison. His cancer was so aggressive that when we wanted a couple of weeks to try one treatment and then change if it wasn’t working, the doctor said, “You don’t have two weeks.” Therefore, we treated aggressively. It saved his life.  Read more HERE.

Undifferentiated cancer
The x-ray on the right shows the rapid increase in cancer in Dan’s lungs.

Everyone has their own way of coping with their cancer. Ours has been to learn as much as possible, trust Dan’s medical team, and pray, pray, pray.


  1. National Cancer Institute, NCI Dictionary of Terms, Undifferentiated
  2. National Cancer Institute, Diagnosis and Staging, Prognosis, Tumor Grade


I am an author, writer, and speaker and homeschooling mom of 3. My husband, Dan has battled stage IV lung cancer since 2012. I help cancer patients and their families advocate for themselves and live life to the fullest, despite their illness.

My goal is to help people face cancer with grace.

My book Facing Cancer as a Friend: How to Support Someone Who Has Cancer, is available on Amazon.com.

The Erickson Family, August 2016. Photo By Jim Bovin


2 thoughts on “Undifferentiated Tumors:”

  1. Thank you so much for sharing your story. I hope that your husband is doing better and that the aggressive treatment was a success. My prayers are with you.

    • Thank you for your prayers, Alice. He is doing well. 5 years of treatment has taken its toll, but he’s with us. We live scan to scan, which he gets every three months. Bless you!

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