Actinomycosis is an underreported chronic invasive disease caused by Actinomyces spp. In that group of diseases, pelvic actinomycosis is very rare and most of the cases reported in the literature have shown unilateral psoas muscle involvement. We report a 35-year-old woman with a retroperitoneal mass located in the left psoas muscle that makes abdominal tenderness and difficulty in walking. |