While angiomyofibroblastoma (AMFB) is uniformly benign in biological behavior, as evidenced by the low Ki-67 proliferation index (10%) in our case and excellent post-resection outcomes reported in literature, its histological overlap with more aggressive mesenchymal tumors like aggressive angiomyxoma creates persistent diagnostic challenges, particularly in unusual anatomical locations such as the retroperitoneum. Here, MKI67 is linked to angiomyxoma.