An unusual cavernous mass

This is a 37 year-old Hispanic female on chronic immunosuppressive therapy with methotrexate for rheumatoid arthritis that then developed right facial pain in the V1 and V2 distribution. Imaging study was performed which showed a lesion in the right cavernous sinus leading to a subsequent biopsy. The biopsy showed inflammatory cells and the patient was treated for inflammation. A year later, she developed a right sixth nerve palsy along with the persistent right facial pain. She then underwent extensive testing.