Primary Small Cell Carcinoma of the Breast: When a Rare Tumour is Real Primary SCC of the breast

Ruba A Hamed (1), Rachel J. Keogh (2), Abdullah Mohammed (3), Maria Twomey (4), Saif Almandhari (5), Deirdre O’Hanlon (6), Seamus O'Reilly (7)
(1) Cork University Hospital, Department of Medical Oncology, Cork, Ireland, Ireland,
(2) Cork University Hospital, Department of medical Oncology, Ireland,
(3) Cork University Hospital, Department of Medical Oncology, Cork, Ireland, Ireland,
(4) Cork University Hospital, Department of Radiology and Breast Imaging, Cork, Ireland, Ireland,
(5) Cork University Hospital, Department of Histopathology, Cork, Ireland, Ireland,
(6) University Hospital, Department of Surgery, Breast Unit, Cork, Ireland, Ireland,
(7) Cork University Hospital, Department of Medical Oncology, Cork, Ireland/Cancer Research Institute, University College Cork, Cork, Ireland, Ireland


Background: Extra-pulmonary small-cell neoplasms are rare, and treatment planning is challenging for clinicians. The lack of guideline-based management undermines and isolates patients for whom these cancers are not just rare but also real. Small-cell breast cancer (SCBC) is a rare, aggressive disease that accounts for less than 1% of all invasive breast cancers. Here, we report a case of SCBC and discuss the complexities of case management.

Case Presentation: A 46-year-old patient presented with a self-detected right breast lump. Mammogram and ultrasound examination showed a 69x47mm dense lesion in the upper outer aspect of the right breast and a 17mm pathologic node in the inferior right axilla. The triple assessment demonstrated a localised high-grade malignant neuroendocrine neoplasm. Management extrapolated from small cell lung cancer management and case reports, consisted of chemotherapy with carboplatin, and etoposide introduced with concurrent radiotherapy, followed by mastectomy with axillary lymph node dissection. A complete pathological response was obtained. Six months following her surgery, metastatic disease in the brain, chest wall, lymph nodes, and lungs developed. Rechallenge with carboplatin and etoposide led to a brief response, and subsequent immunotherapy was ineffective.

Conclusion: This case report highlights the challenges of rare tumour management. Establishing registries for these and other rare tumors would facilitate care, reduce patient uncertainty and assist in founding protocol-based care.

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Ruba A Hamed (Primary Contact)
Rachel J. Keogh
Abdullah Mohammed
Maria Twomey
Saif Almandhari
Deirdre O’Hanlon
Seamus O'Reilly
Hamed R, J. Keogh R, Mohammed A, Twomey M, Almandhari S, O’Hanlon D, O’Reilly S. Primary Small Cell Carcinoma of the Breast: When a Rare Tumour is Real : Primary SCC of the breast. Arch Breast Cancer [Internet]. 2023 Jul. 16 [cited 2024 Apr. 14];10(3):314-9. Available from:

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