Adamantinoma of long bones. A histopathological and immunohistochemical study of 23 cases

The clinical and histological data of twenty-three cases of adamantinomas of the long bone collected by the Working Group on Bone Tumors at the DKFZ/FRG are reported including immunohistochemical observations in twenty-one of the cases. Females and males between 5 and 67 years (mean, 25.4 years) were affected equally (11/12). All adamantinomas were positive for cytokeratins often in coexpression with vimentin, at least focally. Although exhibiting varying histological patterns, no correlation between histology and clinical course was seen. However, sex and mode of initial therapy seem to influence an unfavorable clinical outcome. All three decreased patients were males receiving marginal or delayed surgery. This underlines the low-grade malignant character of adamantinoma. To assure the histological diagnosis pathologists should employ immunohistochemistry for demonstrating the sometimes sparse epithelial cell nests when radiology is suggestive for adamantinoma. Correct diagnosis should lead to resection with wide surgical margins.