Phyllodes tumor is classified into benign, borderline and malignant by World Health Organization, based on nature of tumor border, stromal cellularity, necrosis, mitotic activity and nuclear atypia. [4] They are usually benign, with about 10-25% of cases being malignant.

How do you classify phyllodes tumor?

Phyllodes tumours are classified into benign, borderline and malignant grade categories on the basis of a constellation of histological parameters, i.e. the degree of stromal cellularity and atypia, mitotic count, stromal overgrowth, and the nature of their tumour borders.

Is a phyllodes tumor considered cancer?

Most phyllodes tumors are benign (not cancer), but about 1 out of 4 of these tumors are malignant (cancer).