[Giant cell tumor of bone. Morphological, immunohistochemical, morphometric and DNA flow cytometric findings]

Giant cell tumour (GCT) of bone is a locally aggressive tumour with a high rate of recurrence if not completely excised. The present study was undertaken to clarify whether flow cytometric, immunohistochemical and morphometric studies can be a useful tool to assess the prognosis of patients with GCT. DNA flow cytometry, cell cycle studies and immunohistochemical investigations with antibodies against CD 68, CD 34, p53 and Ki67 were performed on paraffin embedded tissue of 10 cases of GCT. As a further possible prognostic parameter angiogenesis within the tumour was investigated using an automatic image analysis system. Histologically 4 cases were grade 1 tumours and 6 cases grade 2. Among the Grade 1 cases, all were diploid. Of the Grade 2 cases, 4 were diploid and 2 were aneuploid. Both of the patients with an aneuploid tumour developed a loval recurrence. All GCT revealed large numbers of CD 68 positive giant cells, but mononuclear tumour cells exhibiting CD 68 immunoreactivity were also present. Corresponding to the immunohistochemical findings with MIB-1 the flow cytometric DNA histogram revealed high proliferation rates (mean value 14.9%). None of the tumours exhibited p53 immunoreactive cells. All cases showed high content of vessels with on the average relative vessel area of 7.7%. No correlation between clinical outcome and vascular parameters (number of vessels, vessel area, perimeter) was found. Our findings suggest that DNA flow cytometry is useful in predicting tumour behaviour in some cases. GCT exhibits extensive angiogenesis, but none of the vascular parameters investigated was found to be of prognostic value.