Leiomyoma of the seminal vesicle mimicking tumoral extension of prostatic carcinoma.

Leiomyoma of the seminal vesicle is an extremely rare tumour. The diagnosis of this entity is important when it co-exists with prostatic carcinoma, since it can simulate tumour extension from prostate or bladder cancer on MR imaging and lead to overstaging. In this report, we describe a 74-year-old man with a leiomyoma of the seminal vesicle that mimics tumour extension from co-existent prostatic cancer on T2-weighted MR imaging. To our knowledge, this is the first description of imaging findings of concurrent leiomyoma of the seminal vesicle and prostatic carcinoma.