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. In addition, the clinical findings are by no means specific to a tumour type and cannot distinguish between a benign and a malignant tumour, which results in difficulty in diagnosis and management. All paratesticular tumours are amenable to adequate surgical resection. Definite diagnosis is determined by histological evaluation.Leiomyosarcoma, the second most common paratesticular sarcoma after liposarcoma, is represented in the literature primarily as case reports. We report a case of LMS arising from the epididymis and focus on clinical presentation and differential diagnosis of such tumours.