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.