Malignant breast cancer in children: a review of 75 patients.

OBJECTIVE: To determine incidence trends and outcomes for pediatric patients with malignant breast disease.
METHODS: The Surveillance, Epidemiology, and End Results registry was examined for all females 19 years of age and younger diagnosed with a malignant breast tumor between 1973 and 2004.
RESULTS: A total of 75 patients with malignant breast tumors were identified. Overall, 14.5% of patients had in situ tumors, and 85.5% had invasive disease. Tumors were classified as being either carcinomas (n = 41, 54.7%) or sarcomas (n = 34, 45.3%). The majority of sarcomatous lesions were phyllodes tumors (n = 29, 85.5%), whereas most carcinomas were of a ductal etiology (n = 19, 46.3%). The age-adjusted incidence of all malignant pediatric breast tumors in 2003 was 0.08 cases per 100,000 people (0.03 carcinoma and 0.06 sarcoma cases per 100,000 people). In the carcinoma group, regionally advanced disease was present in 11 patients (26.8%), whereas only 3 patients (7.3%) presented with metastatic disease. All patients with sarcomatous tumors presented with localized disease. Adjuvant radiation therapy was administered in only 9.8% of carcinomas and 8.8% of sarcomas, and 85.4% of carcinoma patients and 97.1% of sarcoma patients underwent surgical resection for their primary disease. Subgroup analysis revealed 5- and 10-year survival rates of 89.6% for patients with sarcomatous tumors and 63.1% and 54.3% for carcinomas.
CONCLUSIONS: Malignant pediatric breast malignancies remain relatively rare. The two most common histologies of breast neoplasms in children are malignant carcinomas followed by sarcomas. Although uncommon, malignant disease must be considered in the differential diagnosis of the pediatric patient with a breast mass.