Paratesticular leiomyosarcomas are exceedingly rare tumors. Most of them arise in older men (median age at presentation is around 64 years; range 35-85 years) and involve testicular tunics or spermatic cord. Rare cases involve epididymis, scrotal subcutaneous tissues or dartos muscle. The tumors are usually well-circumscribed (as seen in this image) and large (median size around 4 cm; range 2-10 cm). Image courtesy of Dr. Montemor Netto, Brazil; Used with permission.
Ref: Fisher C et al. Leiomyosarcoma of the Paratesticular Region: A Clinicopathologic Study. Am J Surg Pathol 25(9):1143-1149, Sept. 2001.