Welcome to Connect @traillens47. You’re looking for information of the prognosis of living with CLL beyond 20 years. From my perspective of having had a very aggressive form of leukemia, anyone living healthfully for 20+years with a chronic form of leukemia is enjoying a pretty normal life span.

Without treatment CLL and SLL both tend to develop slowly over years. They are essentially the same disease it just depends on where most of the cancer cells are concentrated. CLL is found in the blood and marrow of a patients, while with SLL the disease is in the lymph nodes. From my understanding, the distinction between CLL and SLL does not influence the outlook of the disease and they’re both treated the same as the cells are indistinguishable under a microscope.
Here’s a little informational article comparing CLL to SLL:
https://www.healthline.com/health/leukemia/cll-vs-sll
While searching for statistics on patient survival beyond 20 years, the reports I did find seemed outdated because of the changes in treatments over the past 20 years. CLL/SLL are still not ‘curable’ but with new treatments that are now available, the disease is often caught earlier and people are monitored more closely. When treatment is warranted, the newer, targeted drugs can make a huge different in slowing the progression of disease giving patients a pretty normal life span.

I wasn’t familiar with Pyoderma gangrenosum, but what I found is that it’s an inflammatory skin disease and people with underlying conditions, such as blood disorders are more prone to developing this condition. This would be a good question to ask your doctor about the relationship between your SLL/CLL and pyoderma gangrenosum. I’m not a medical professional but had AML. After treatment, I did develop a couple of skin issues that are now gone. But they were felt to be a relationship with my compromised immune system and nothing to do with the cancer itself.
https://www.merckmanuals.com/home/skin-disorders/hypersensitivity-and-reactive-skin-disorders/pyoderma-gangrenosum
Have you been in treatment for your CLL for the past 15 years? What does your oncologist suggest now that you’ve also been diagnosed with SLL?