Clinical outcomes in patients with adamantinoma: Report from the bone and soft tissue tumor registry in Japan

Background Adamantinomas are rare malignant bone tumors. Due to their low incidence, there are few reports on the clinical results of adamantinoma. Objectives This study aims to clarify outcomes in patients with adamantinoma using data from the National Bone and Soft Tissue Tumor Registry. Methods From 2006 to 2019, 38 cases of tibial origin were included. Twenty‐four were male and 14 were female, with a mean age of 37 (6–87) years and a mean follow‐up of 35 (1–128) months. Results Surgery was performed in 33 cases (87%) (curettage: 4 cases, wide resection: 27 cases, amputation: 2 cases). Reconstruction was performed in 27 patients who underwent wide resection. A total of 12 additional surgeries were performed in 11 patients. The main reason for the additional surgeries was nonunion of grafting bone in 6 cases. Oncologic outcomes were DOC (death from other causes) in one case and NED (no evidence of disease) in 37 cases. Conclusions The results of treatment of adamantinomas in Japan have been extremely favorable. This may be due in part to the large number of cases with wide resection.