Rationale

Metastatic neuroendocrine neoplasms (NENs) to the breast are very rare entities comprising only 1% to 2% of all metastatic breast tumors. In this article, we describe a case of a neuroendocrine ileal neoplasm metastatic to breast and liver, with breast metastatic tumor to be the initial manifestation of the disease.

Patient concerns

We herein report a rare case of a female patient admitted to our department with a palpable painful mass on her left breast.

Diagnosis

The surgical and histological investigation revealed a metastatic neuroendocrine neoplasm to the breast originated from terminal ileum.

Interventions

A left lumpectomy, right hemicolectomy, cholecystectomy, left hepatectomy along with liver metastasectomies (V, VI, VIII) plus radiofrequency ablation of lesions to the right liver lobe plus standard lymphadenectomy was performed.

Outcomes

Considering the advanced stage of the disease, the patient received an adjuvant therapy of somatostatin analog plus everolimus. Under the guidance of oncological consultation, patients follow-up with CT and MRI scan and clinical re-evaluations in the first 3 and 6 months, substantiates no evidence of recurrence and she presents herself asymptomatic.

Lessons

An appropriate level of suspicion and selective immunohistochemistry in these cases, particularly where no prior history of a known primary neuroendocrine neoplasm occurs, may help to diagnose a previously undetected neuroendocrine tumor elsewhere in the body and provide guidance for the appropriate treatment selection.