Test Scenario: Test scenario is like laying out plans for testing the product, environmental condition, and number of team members required, making test plans, making test cases and what all features are to be tested for the product. Test scenario is very much dependent on the product to be tested. Test scenario is made before the actual testing starts.
Test Case: Test case is a document which provides the steps to be executed which has been planned earlier. It also depends on the type of product to be tested. Number of test cases is not fixed for any product.