The 19-year-old revealed the news on Thursday in a 'Goodbye Hospital' video on her YouTube channel ... one month after her final treatment for a brain tumor.

The clip shows Isabella at the Duke Children's Hospital & Health Center in Durham, North Carolina ... where she had her chemotherapy port surgically removed, something she was excited about, despite it being a painful procedure.

"My side hurts a lot. It feels like I got stabbed," Isabella said showing her post-op bandages.

"I also feel like the tube was going into my heart because my heart started cramping. I don’t know if that’s supposed to happen but, not enjoyable."

Now for the great news. The visit this week was to go over MRI scans ... which confirmed the cancer was gone!

"Great scans, everything was clear. Cancer-free," she said. "I don’t have another doctor’s appointment until October."

It's been a helluva journey for the model who was diagnosed with medulloblastoma, a rare malignant tumor located at the base of her brain, last October.

She shared every step of the way with her fans after going public with the battle this January ... from emotional moments to setbacks during chemo.