Metastasis to Breast from Extramammary Solid Tumors and Lymphomas: A 20-Year Population-Based Study

Breast metastases from extra-mammary cancers: A report of 3 challenging cases and literature review

We report 3 cases of patients with a history of extra-mammary cancer who presented with breast nodules, leading to diagnostic challenges and occasional misleading imaging findings. These cases highlight the significance of radiologists considering breast metastases as a potential component of the differential diagnosis when assessing patients with a history of cancer who exhibit palpable breast nodules. Furthermore, these cases underscore the importance of integrating various imaging techniques with histological and immunohistochemical analyses of the lesions to achieve precise diagnoses, ultimately ensuring the highest quality of care for these patients.

Breast metastases from non-primary breast malignancies: What should we know?

BACKGROUND

Metastases from extramammary malignant neoplasms are very rare, accounting for less than 2% of all breast malignancies.

OBJECTIVE

The aim of this study is to describe the clinicopathological features and prognosis of breast metastases from non-primary breast malignancies at our institution.

METHODS

We performed a retrospective observational study, obtaining data from electronic medical records and pathology databases between January 1985 and December 2020 for patients diagnosed with breast metastasis from non-primary breast malignancies. Only patients diagnosed by biopsy were included.

RESULTS

Fifteen patients diagnosed with breast metastases from non-primary breast malignancies were included, 13 women (86,67%) and 2 men (13,33%). The median age at time of initial diagnosis was 56 years (IQR 21-68). The most frequent primary malignancy was melanoma (9/15; 60%). The median time to diagnosis of breast metastases was 65 months (IQR 13-106). The most common diagnostic modality was CT-scan (10/15; 66,67%). The median follow-up was 96 months (IQR 29-136). Eight patients underwent surgery (53,3%), being the most common surgical intervention breast-conserving surgery (5/8; 62,5%). Mortality at the end of follow-up was 53,3% (8/15). On the survival analysis, we found no differences between patients undergoing surgery and those only receiving systemic treatment [41,5 months (IQR 17,5-57,5) versus 14 months (IQR 2-24), respectively; p = 0,161].

CONCLUSIONS

Breast metastases from non-primary breast malignancies are extremely rare and represent a diagnostic and therapeutic challenge, due to the poor prognosis of these patients. Thus, arriving at the correct diagnosis is crucial to avoid unnecessary treatment in this population.