Breast metastasis from large cell neuroendocrine carcinoma of the lung: a case report

Abstract Background Primary breast carcinoma is far more common than breast metastases. Common breast metastases usually come from lymphoma, leukemia, melanoma, and ovarian cancers. Breast metastases from neuroendocrine carcinomas are considered an exceeding rare entity. It has been reported in the literature that the pathological presentation of this particular metastatic tumor is very challenging as it shares many morphological characteristics with primary breast carcinoma. Case presentation We report a case of a patient with large cell neuroendocrine carcinoma of the lung metastasizes to both breasts. The patient was initially presented with brain metastasis of unknown origin. Further radiological imaging workup showed multiple bilateral breast masses and bilateral lymphadenopathy, which raised concern for secondary lymphoma of the breast. The histopathology of this case was challenging, particularly when triple negative invasive ductal carcinoma diagnosis had been made. Multidisciplinary meetings between medical oncologists, radiologists, and pathologists profoundly helped confirming the diagnosis of metastatic large cell neuroendocrine tumor to the breast. Conclusion Large cell neuroendocrine carcinoma of the lung is a relatively uncommon diagnosis with generally poor prognosis. Large cell neuroendocrine carcinoma that metastasizes to the breast is even scarcer. Correlation between clinical assessment, radiological imaging, and pathological evaluation is the key in making such an unusual and complex diagnosis. Additionally, radiologists should be aware of metastatic presentations of the breast and avoid confusion with mimicking benign entities or primary breast carcinomas.