Metastatic endometrial endometrioid carcinoma with clear cell changes to the breast: a case report

Metastasis to breast from extramammary tissue is rare, and endometrial cancer has rarely been reported to metastasize to the breast. An extensive search in the medical literature reveals only 2 cases. They can be easily mistaken for primary breast carcinoma both clinically and radiologically, even with known history of endometrial carcinoma. This report presents a case of a 64-year-old woman who had endometrial carcinoma treated with total hysterectomy and adjuvant radiation and chemotherapy. Three years after the diagnosis, she had evidence of a solitary breast metastasis. To our knowledge, this is the third described case of endometrial cancer metastatic to the breast and the first in which the endometrial carcinoma demonstrates significant clear cell changes. This report is a reminder that although rare, endometrial carcinoma has the potential to metastasize to breast and illustrates how metastatic lesions in the breast can masquerade clinically as a primary carcinoma. Furthermore, essential guidelines necessary to distinguish primary from metastatic lesions in the breast are presented.