Imaging, clinical, and histopathological challenges in diagnosing retroperitoneal extraskeletal osteosarcoma - Ichikawa, Jiro; Kawasaki, Tomonori; Onohara, Kojiro; Wako, Masanori; Taniguchi, Naofumi; Ochiai, Satoshi; Haro, Hirotaka (Frontiers in Oncology, 2025)