Increased microvessel density in malignant and borderline mammary phyllodes tumours

Aims: Tumour vascularity is considered a prognostic indicator in breast car cinoma, but its utility in mammary phyllodes tumour was not been explored. The authors report the correlation between intratumoral microvessel density and the histological grade of phyllodes tumour. Methods and results: Forty cases of phyllodes tumour were reviewed for stro mal cellularity, overgrowth, cytological pleomorphism, mitotic count and ma rgin pattern, Using established criteria, these were diagnosed as benign (n = 28), borderline (n = 10) and malignant (n = 2). Microvessel density was counted on CD31-stained slides as the number of vessels per high power fiel d. For benign phyllodes tumour, the range was 7-26.2 (mean 13.1); for borde rline phyllodes tumour the range was 17.2-32.5 (mean 22.4); for malignant p hyllodes tumour the range was 25.9-33.3 (mean 29.6). The difference between the benign and borderline groups was significant (P < 0.0001) but that bet ween the borderline and malignant groups was not, due to the small number o f malignant cases. Conclusions: There is a significant difference in stromal microvessel densi ty between benign and borderline phyllodes tumour. Although the small numbe r of cases of malignant phyllodes tumour limits further interpretation, we believe that microvessel density can be used as an additional objective his tological parameter in the evaluation of phyllodes tumour.