Nilotinib in Patients With Relapsed or Metastatic Pigmented Villonodular Synovitis/Tenosynovial Giant Cell Tumor/Diffuse-Type Giant Cell Tumor

* In this research study, each cycle of study drug dosing will last 4 weeks (28 days). During each cycle, participants will take nilotinib by mouth twice daily. During the first cycle, participants will come to the clinic on Days 1 and 8. For Cycles 2-4 and every 3 cycles thereafter, they will come to the clinic on Day 1. * The following tests and procedures will be performed at specific time points during study treatment: MRI or CT scans; physical examinations; vital signs; blood work; questionnaires and EKG. * Participants may continue in this research study for as long as they do not have serious side effects or their disease does not get worse.