Adamantinoma of long bones: a long-term follow-up study of 11 cases.

The aim of this study was to evaluate the clinicopathological features and prognostic significances of 11 histologically proven adamantinoma cases based on an average 12,7 year long follow-up. The male: female ratio was 8:3, aged between 4 and 80 years (mean 29,3 years). The initial diagnosis at referral was other than adamantinoma in six patients (fibrous dysplasia, carcinoma metastasis, osteofibrous dysplasia, bone cyst, non-ossifying fibroma), referring to the differential diagnostic problems. All tumors were localized to the mid part of tibia. By histological evaluation, basaloid pattern on a background of fibrotic stroma dominated in six patients, while spindle and squamous features were less frequently seen. All adamantinoma were positive for cytokeratins often in coexpression with vimentin. No correlation was experienced between histology and clinical outcome. Intralesional curettage (2 pts) was followed by recurrence of the tumor. Wide resection was performed in eight patients with reconstruction using intercalary fibula autografts in seven patients. Reconstruction-related complications occurred in two third of the cases, all of them could however be controlled by repeated surgery. Six recurrences occurred in four patients, two of these recurrences occurred 20 and 16 years after initial surgery. One patient died 9 years after recognition of the tumor of pulmonary metastases. Adamantinoma of the long bones is a low grade malignant tumor, which clinical outcome is difficult to predict based on histology or surgical stage of the tumor. Wide surgical margin, e.g. resection the tumor reduces the rate of recurrence. This study underlines that recurrences do occur even decades after recognition the tumor, therefore a life-long follow-up of the patient is necessary.