The MRI sequences demonstrate a well-defined intramuscular mass within the gluteus maximus measuring 10 x 7.5 x 6 cm, of isosignal to the muscle on T1 with a peripheral rim of fatty signal, heterogeneous high signal on T2 and STIR with no restricted diffusion. The postcontrast dynamic sequences show a progressive peripheral enhancement with a heterogeneous incomplete fill-in on delayed sequences.