AuthorizationGroups.cs

namespace definition
{
    public class AuthorizationGroup
    {
        public string[] Groups { get; set; }
    }
}

LoginCallback.ashx.cs

using Newtonsoft.Json;
using definition;

public override async Task ProcessRequestAsync(HttpContext context)
{
///...
///...
            var auth = profile.AppMetadata["authorization"];
            if (auth !=null)
            {
                //{{  "authorization": {    "groups": [      "Administrator"    ]  }}}
                AuthorizationGroup authorization = JsonConvert.DeserializeObject<AuthorizationGroup>(auth.ToString());
                foreach (var role in authorization.Groups)
                {
                    user.Add(new KeyValuePair<string, object>(ClaimTypes.Role, role));
                }
            }
///...
///...
}

someview.cshtml

@if (User.IsInRole("Administrator"))
{
  <h1>Administrator.FTW</h1>
}