Case report

primary neuroendocrine carcinoma of breast

Abstract

Osaid Mahmoud Awwad Shoail. MD, Alhareth Ali Hasan Azaizeh. MD, Mothana Yousef Al-Nawaflh. MD, Duha Zaidan Abdel Samad Al-Khamaiseh. MD, Tariq Abdullah Mohammad Alomari. MD, Oadi Abduljalel Ibrahim Al-Wraikat. MD

Introduction: Primary neuroendocrine carcinoma (PNEC) of the breast is a rare subtype of breast cancer, often diagnosed in postmenopausal women and typically associated with aggressive clinical behavior. Histological features and the immunohistochemistry expression of neuroendocrine markers constitute the basis for the diagnosis. Due to its rarity, standardized treatment protocols are lacking.

Case Presentation: We report a case of a 38-year-old premenopausal female who presented with a painless left breast mass. Imaging revealed a suspicious lesion, and core biopsy confirmed invasive mammary carcinoma with neuroendocrine differentiation. Immunohistochemistry was positive for chromogranin, synaptophysin, and NSE, confirming the diagnosis. The patient underwent neoadjuvant chemotherapy (dose-dense AC followed by Taxane), followed by breast-conserving surgery and sentinel lymph node biopsy. Due to close surgical margins, she later underwent a nipple-sparing mastectomy with implant reconstruction. Despite systemic therapy, the patient developed liver metastases with a Ki-67 index of 100%, necessitating platinum-based chemotherapy.

Conclusion: This case highlights the aggressive nature of PNEC, particularly in younger patients, and underscores the need for heightened clinical suspicion, multidisciplinary management, and further research to guide treatment strategies for this rare malignancy.

Keywords: Neuroendocrine tumor, breast carcinoma, diagnosis, immunohistochemistry, metastases

Osaid Shoail