Modern medicine was imported to Japan from Germany 150 years ago, and Japanese physicians still employ German expressions like “Magenkrebs” (gastric cancer) and “Karte” (medical record). Another such term is “Insel” (island), used to describe a distinctive endoscopic feature occasionally observed within the depressed regions of early gastric cancer (EGC). Endoscopic examination of a 74-year-old woman with EGC revealed the Insel phenomenon (Figure). The surface of an Insel may contain cancerous tissue but often shows less tumor infiltration than the surrounding depressed areas. This unique feature has led to the use of the Japanese terms, such as “island-like mucosal remnants” and “sanctuary” (the inviolable area without cancer invasion) to describe these regions, in addition to the more idiomatic Insel. The Insel is frequently found in the undifferentiated-type EGC, such as signet-ring cell carcinoma, with a tendency for aggressive invasion and spread. Therefore, surgery is often preferable to endoscopic submucosal dissection.
Figure.
Endoscopy showed an Insel (arrow) located within the depressed regions of early gastric cancer.
Footnotes
Conflict of interest statement: The authors state that they have no conflict of interest.