Tricky Tumors Hiding Out (IMAGE) Ecole Polytechnique Fédérale de Lausanne Caption The tumor has transformed its outer layer into lymphoid-like tissue to avoid detection by the immune system. Credit EPFL Usage Restrictions EPFL License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.