Presentation
Recurrent vaginal bleeding.
Patient Data
The uterus shows multiple small interstitial fibroids showing typical features of fibroid being of isointense signal on T1 and low signal on T2 WI with minimal post-contrast enhancement and no diffusion restriction.
However, there is a large right subserosal fibroid with atypical imaging features including high signal on T2 WI with mild heterogeneity, diffusion restriction with mildly low ADC values, and intense post-contrast enhancement. No internal areas of breakdown or hemorrhage.
The patient underwent panhysterectomy which revealed a hypercellular subserous uterine fibroid with no dysplasia or malignancy.
Radiological features of hypercellular fibroid
Intermediate to high signal on T2 WI
Diffusion restriction on DWI
Intense post contrast enhancement.
Case Discussion
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.
DDx:
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.