Typical features of uterine fibroids include hypointense signal on T2, loss of diffusion restriction, and minimal contrast enhancement.
Hypercellular uterine fibroids represent an atypical type of fibroids, pathologically they are soft, compact structures with increased cellularity, no collagen, and abundant blood vessel, yet with no dysplasia or malignancy. Radiologically, they appear of intermediate to high signal on T2, diffusion restriction, and avid homogeneous contrast enhancement.
The main differential is a uterine leiomyosarcoma which usually occurs in postmenopausal older females. They are usually poorly demarcated and show aggressive features such as areas of hemorrhage and necrosis with heterogeneous contrast enhancement with internal non-enhancing areas. They show diffusion restriction and markedly decreased ADC values.