Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder that affects approximately 1 in 3000 births. Retroperitoneal tumors occur in 2%-5% of NF1 patients and pose diagnostic and therapeutic challenges. We report a 25-year-old male from Cape Verde with confirmed NF1 who presented with progressive abdominal pain and a 15 x 11 x 12 cm retroperitoneal mass in the left psoas muscle. He underwent a successf...