Phyllodes tumors of the breast are rare, accounting for less than 1% of all breast tumors. The name "phyllodes," which is taken from the Greek language and means "leaflike," refers to that fact that the tumor cells grow in a leaflike pattern. Other names for these tumors are phylloides tumor and cystosarcoma phyllodes. Phyllodes tumors tend to grow quickly, but they rarely spread outside the breast.

Although most phyllodes tumors are benign (not cancerous), some are malignant (cancerous) and some are borderline (in between noncancerous and cancerous). All three kinds of phyllodes tumors tend to grow quickly, and they require surgery to reduce the risk of a phyllodes tumor coming back in the breast (local recurrence).

Phyllodes tumors can occur at any age, but they tend to develop when a woman is in her 40s. Benign phyllodes tumors are usually diagnosed at a younger age than malignant phyllodes tumors. Phyllodes tumors are extremely rare in men.

On the following pages, you can learn more about:

• How Phyllodes Tumors Develop in the Breast
• Symptoms and Diagnosis of Phyllodes Tumors of the Breast
• Treatment of Phyllodes Tumors of the Breast
• Follow-up Care for Phyllodes Tumors of the Breast