Calling the discovery of a new organ in the human body surprising is a bit of an understatement, but that's what a study published March 27 in Scientific Reports claims.

According to the study, co-led by Neil Theise, MD, a pathology professor at NYU Langone Health in New York City, researchers used microscopic technology to identify living tissues, finding that layers of the body are interconnected through compartments filled with fluid. 

The compartments were found with probe-based confocal laser endomicroscopy technology, which combines an endoscope slid down the throat with a laser that lights up tissues and sensors that identify reflected fluorescent patterns, according to an NYU press release.  

The "highway of moving fluid,” as the researchers refer to the newly discovered organ, is located below the skin's surface and between muscles around the digestive tract, lungs, urinary system and surrounding arteries and veins, the researchers wrote. Flowing directly in the lymphatic system, the newly discovered organ may suggest why cancer tends to spread throughout the body. The researchers also explained in their findings that the cells in this fluid filled network may help prevent tearing of tissues, muscles, and vessels while functioning and may potentially aide in skin aging to the progression of inflammatory diseases. 

“This fixation artifact of collapse has made a fluid-filled tissue type throughout the body appear solid in biopsy slides for decades, and our results correct for this to expand the anatomy of most tissues,” Theise said in an NYU press release. “This finding has potential to drive dramatic advances in medicine, including the possibility that the direct sampling of interstitial fluid may become a powerful diagnostic tool.”

Researchers collected tissue specimens of bile ducts during 12 cancer surgeries and underwent confocal microscopy for live tissue imaging minutes before stopping blood flow to the targeted tissue, according to study methods.  

"The cells may also be mesenchymal stem cells, which are known to be capable of contributing to the formation of scar tissue seen in inflammatory diseases," Theise said. "Lastly, the protein bundles seen in the space are likely to generate electrical current as they bend with the movements of organs and muscles around them and may play a role in techniques like acupuncture."