What Is a Cystosarcoma Phyllode?

A rare breast tumor most commonly seen in middle-aged women, a cystosarcoma phyllode is a growth that arises from the cells making up the tissue of the breast. Although most often these tumors are benign, sometimes they do have the ability to grow into surrounding structures and to distant parts of the body. Diagnosis of the tumor relies on taking a sample from the mass, and treatment focuses on removing the abnormal breast tissue.

A cystosarcoma phyllode tumor is thought to form in the stromal cells of the breast. These cells make up the breast tissue, and can grow and divide in response to high levels of hormones in the blood, such as estrogen or progesterone. For unknown reasons, in rare cases these stromal cells can begin to multiply in an unregulated fashion, and can even invade surrounding structures or spread to far-away regions of the body. This unregulated growth of stromal cells causes the development of the cystosarcoma phyllode tumor.

Risk factors for the development of a cystosarcoma phyllode tumor are poorly understood. The tumors typically appear in women in their forties. Often, women who develop the tumor at a later age have disease that is more difficult to treat. A rare genetic condition known as Li-Fraumeni syndrome is known to cause this type of tumor.

The definitive diagnosis of a cystosarcoma phyllode tumor relies on taking a biopsy of the mass and inspecting it under the microscope. The tumor itself might be detected by self breast exam, clinical breast exam by a licensed medical practitioner, or by mammography — a radiographic procedure used to look for abnormalities in the breast tissue. After a mass is identified, it can either be biopsied by removing a small section of the tumor, or can immediately be fully removed.

Treatment of a cystosarcoma phyllode tumor focuses on its surgical removal. Specialists in breast surgery carefully remove the tumor, making sure to remove all of the abnormal tumor tissue. Resected tissue is typically then sent to a pathologist who can review the margins to ensure that the entire tumor was removed.

The prognosis of a patient suffering from a cystosarcoma phyllode tumor depends on a number of factors. Many of these tumors are benign, meaning that by nature they do not infiltrate surrounding structures or spread to distant parts of the body. Prognosis in these patients is typically good, although they do have to be monitored for future recurrence of the disease. If the tumor is malignant, meaning that it does have the propensity to spread to different regions, achieving a cure from the disease is more difficult. These patients might require chemotherapy or radiation therapy in order to more completely eradicate the tumor.