While the interstitium is currently being described as an organ in the study today, further research will be required before this can be confirmed.
If it is, it will be classed as one of the largest organs in the human body.
Until now, scientists thought that the interstitium was nothing more than dense connective tissue.
However, during a routine endoscopy of a bile duct, doctors realized that they were looking at what appeared to be a network of capillaries.
After this discovery was made, doctors approached New York University pathologist Dr. Neil Theise to try and identify what they had found.
It was then that doctors realized no one had discovered the interstitium before because fluid is usually drained away before the tissue is examined under a microscope - an act which would destroy the structure of the "organ".