Affiliation: | 1. Department of Surgical Pathology, Sapporo Medical University, School of Medicine, Chuo‐ku, Sapporo, Hokkaido 060‐8543, Japan;2. Department of Orthopedic Surgery, Sapporo Medical University, School of Medicine, Chuo‐ku, Sapporo, Hokkaido 060‐8543, Japan |