PRIMARY ANGIOSARCOMA OF THE BREAST: IS KI-67 proliferation index related to histologic grade? Does steroid hormone receptor expression play a role in the frequency of coexistent pregnancy?

AIMS: The aim of this study was to investigate the relationship between Ki- 67 proliferation index and prognosis in primary angiosarcoma of the breast (PAB). Hormonal status of PAB was also discussed, since PAB sometimes can be seen with coexistent pregnancy.METHODS: During a 17-year period 4 cases of PAB were established out of almost 5000 breast biopsies. Immunohistochemical analyzes were performed for antibodies against CD31, CD34, estrogen receptor (ER) and progesterone receptor (PR). Ki-67 proliferation index was also investigated.RESULTS: All patients clinically presented with a palpable mass. The mean patient age at diagnosis was 40.8 years (29-56). Two patients were at the end of their first trimester in pregnancy. The mean score of Ki-67 index was 28.7% (2-55%). Two patients with Grade I tumor and with the lowest Ki-67 index were alive with no evidence of disease 7-8 years after surgery. Proliferation index was detected to be 50% in Grade II tumor, and the patient has been receiving radiotherapy and chemotherapy because of distant metastases. The patient with Grade III tumor died with disseminated disease one year after the initial diagnosis. Positive immunoreactivity for ER and PR could not be detected in any tumor.CONCLUSIONS: Since, it was previously stated that grading is the most important prognostic indicator, we suggest that Ki-67 proliferation index may also be used for the same purpose. No evidence of an association with hormonal status could be drawn.