Neuroendocrine Neoplasm of the Breast Presenting as a Liver Metastasis: A Rare Diagnostic Challenge

We present a case of a 58-year-old female who presented initially to an outside institution with abdominal pain and was diagnosed on liver biopsy with a well-differentiated neuroendocrine tumor of an unknown primary source. She was referred to our academic institution for a second opinion after disease progression on the initial chemotherapy regimen. Through additional evaluation, diagnostics, and multi-disciplinary tumor board discussion she was diagnosed with metastases from a well-differentiated neuroendocrine neoplasm of the breast (NENB). Consequently, her treatment plan was modified leading to significant clinical and radiological improvement.