diff --git a/Packages-react/extensions/ohif-cornerstone-extension/package.json b/Packages-react/extensions/ohif-cornerstone-extension/package.json
index 5eed62544..a5daa92b3 100644
--- a/Packages-react/extensions/ohif-cornerstone-extension/package.json
+++ b/Packages-react/extensions/ohif-cornerstone-extension/package.json
@@ -26,6 +26,7 @@
     "dcmjs": "^0.3.3",
     "dicom-parser": "^1.8.3",
     "hammerjs": "^2.0.8",
+    "prop-types": "^15.6.2",
     "react": "^15.0.0 || ^16.0.0",
     "react-dom": "^15.0.0 || ^16.0.0",
     "react-redux": "^6.0.0",