Epithelioid type of paratesticular leiomyosarcoma: a case report and literature review.

Paratesticular leiomyosarcoma is a rare neoplasia, which has been reported in less than 100 cases so far. According to its prevalence, this neoplasia is originated from testicular tunica (48%), spermatic cord (48%), epididymis (2%) and dartos muscle, as well as subcutaneous tissue of scrotum (2%).(1,2,3) This lesion is seen in all age groups. However, it is mostly diagnosed in the 6th decade and more than 80% of patients are over 40 years old.(4) Leiomyosarcoma is the result of neoplastic transformation of smooth muscle cells or multipotential mesenchymal cells in various sites of the body.(1,5) The behavior of these lesions depends on the site of origination, but little is known for grading of such tumors in paratesticular region.(4,6) Like other mesenchymal tumors of this region, leiomyosarcoma is manifested as a painless mass without hydrocele and the disease may be symptomatic in less than one year. Size of tumor is usually between 2 and 9 cm with a mean of 5 cm. Almost all cases are primary lesions rather than the extension of a retroperitoneal lesion.(2)