Secondary neoplasms of the breast

BACKGROUND: A 90-year archive of surgical and postmortem material was reviewed to establish the incidence, presentation, and pathology of tumors secondary to the breast. METHODS: A search was performed on all cases contained within the files of the Pathology Department of the Royal London Hospital from 1907 to 1999. RESULTS: Sixty patients were identified with unequivocal, secondary, nonmammary neoplasms involving the breast. Hematologic tumors predominated, particularly among the more recent cases, with carcinoma less frequent overall but more numerous in the earlier part of the 20th century. There were several surprising and sometimes unique findings, with occasional metastases from primary tumors of the esophagus, retina, pancreas, thyroid, and skin. Other primary tumor sites included the stomach, lungs, and kidney. In line with expectations, the majority of tumors occurred in women. CONCLUSIONS: Secondary tumors to the breast are rare. In the current series, these tumors comprised 3% of the breast tumors in the files under review. The majority of these were metastases from the contralateral breast. However, the existence of metastatic nonmammary tumors to the breast should be appreciated so that secondary tumors from unusual sites are not overlooked, particularly with the widespread use of fine-needle aspiration cytology and needle core biopsies for preoperative diagnosis. In fact, 0.43% of the breast malignancies in the current report originated from sites outside the breast. Of these one-third represented spread from an occult primary. Furthermore, the current data suggest a move from carcinomatous metastases to hematologic malignancies over the last century, possibly reflecting earlier diagnosis of the former and an increase in the prevalence of the latter.