Edema of the bone marrow at the base of the ulnar styloid (appreciated on coronal PD fat sat) with interruption and irregularity of the cortex (best appreciated on coronal T2). There is a fluid containing structure just superior to the ulnar styloid having a narrow tail connected to the the ulno-carpal joint (best appreciated on axial T2 sequence). Abnormal signal intensity is also seen at the triangular fibrocartilage suggesting ligamentous injury. There is also mild effusion at the ulno-metacarpal joint.
Conclusion: Old fracture of the ulnar styloid with secondary degenerative changes, ganglion cyst and possible ligamentous injury to the triangular fibro-cartilage.