A rare cause of a scrotal mass: primary leiomyosarcoma of epididymis.

Most masses encountered within the scrotal sac are neoplastic and occur within the testis; however a subset (2-3%) of these tumours is extra-testicular and usually arises from paratesticular tissue. Although uncommon, these tumours have a high incidence of malignancy reaching 30%, mainly represented by sarcomas (90%). Tumours occurring in the paratesticular region may be clinically indistinguishable from testicular tumours, thus resulting in initial misdiagnosis.