Clinicopathological observation of adamantinoma of long bone

Objective To investigate the clinicopathological features and differential diagnosis of adamantinoma of long bone. Methods Seven cases of adamantinoma on long bone were selected at Jiangsu Province People′s Hospital from June 2012 to May 2018. Clinicopathologic details, immunohistochemical and molecular analysis were performed,and the relevant literature reviewed. Results There were 6 males and 1 female patients,age ranging from 21 to 60 years (mean 38 years). Six cases were on the right side and one case was on the left; in five cases the tumors arose from tibia, one from patella and one from humerus. Microscopically,tumour cells were mainly composed of spindle cells arranged in bundles or braids,with irregular epithelial island. Immunohistochemically,the epithelial island expressed high molecular weight cytokeratin but not CK8/18. Both epithelial and spindle components expressed vimentin. One case that was microscopically similar to intraosseous synovial sarcoma did not show SYT gene rearrangement. Clinical follow-up was available for five patients: one patient had axillary metastases seven months after operation, one patient had recurrence 34 months after surgery, 3 patients were uneventful with follow up duration from half a month to 32 months. Conclusion Adamantinoma occurring in long bones is very rare. The correct diagnosis requires adequate sample selection, careful morphologic observation, immunohistochemistry and molecular genetics. Key words: Adamantinoma; Diagnosis,differential; Pathology,clinical