ABSTRACT
Purpose To investigate the diagnosis and differentail diagnosis of metastatic small cell carcinoma of bone in needle biopsy, especially for the differentail diagnosis with Ewing sarcoma of bone. Methods Clinicopathological informations of 11 cases of metastat-ic small cell carcinoma and 20 cases of Ewing sarcoma were collected, and markers for differentail diagnosis were detected in two groups by immunohistochemistry of EnVision. Results The positive rates of CD99 and FLI-1 were 27. 3% and 54. 5% in metastatic small cell carcinoma group, while the positive rate of CK was 15. 0% in Ewing sarcoma group. Patient′s age, single lesion, expression of CK, vimentin, CD99, FLI-1, CD56 were significantly different in two groups. Conclusions Metastatic small cell carcinoma and E-wing sarcoma share similar histopathologic features in needle biopsy, no single immunohistochemical marker can specifically distinguish small cell carcinoma from Ewing sarcouma. The correct diagnosis should comprehensive analyze clinicopathologic characters and a se-ries of immunohistochemical markers.