diff --git a/src/applications/diffusion/conduit/DiffusionQueryPathsConduitAPIMethod.php b/src/applications/diffusion/conduit/DiffusionQueryPathsConduitAPIMethod.php
--- a/src/applications/diffusion/conduit/DiffusionQueryPathsConduitAPIMethod.php
+++ b/src/applications/diffusion/conduit/DiffusionQueryPathsConduitAPIMethod.php
@@ -79,7 +79,8 @@
     $offset = (int)$request->getValue('offset');
 
     if (strlen($pattern)) {
-      $pattern = '/'.preg_quote($pattern, '/').'/';
+      // Use '#' as delimiters, escaping ones already present in the pattern.
+      $pattern = '#'.str_replace('#', '\#', $pattern).'#';
     }
 
     $results = array();