Supplementary Material for: A case of bilateral synchronous paratesticular leiomyoma

Bilateral synchronous paratesticular leiomyoma (BSPL) is a rare tumor that originates from smooth muscle cells in the paratesticular region. Four BSPL cases have been reported sporadically, starting with the 1991 report by Aus and Boiesen. Herein, we report the case of a 60-year-old male with a bilateral scrotal mass with a maximum size of 7.5 cm. Histological examination revealed oval to spindle-shaped tumor cells with a fascicular growth pattern. Immunohistochemically, the tumor cells were positive for α-smooth muscle actin. The pathological diagnosis was a leiomyoma. Based on the simultaneous bilateral nature of the disease, BSPL was diagnosed. In conclusion, we encountered a rare case of BSPL, and our report may contribute to the understanding of this disease.