Primary small cell neuroendocrine carcinoma of the breast - A case report and review of the literature

Abstract

Introduction: Primary small cell neuroendocrine carcinoma of the breast (SCNCB) is a very uncommon type of breast cancer. Histology and morphology are virtually indistinguishable from small cell neuroendocrine carcinomas of the lung (SCNCL), mandating a search for a primary site elsewhere in the body. There is no standard approach to treatment as there are only a limited number of cases reported in the literature. This report summarizes a case of primary SCNCB and presents a review of the literature.

Presentation of case: A 65-year-old female presented to her gynecologist with a right breast mass. After biopsy, she was diagnosed with a primary SCNCB with regional lymph node involvement. She was treated with chemotherapy and radiation therapy with a good clinical response.

Discussion: Due to the rare nature of this tumor, no standard treatment exits. Case reports have described breast conserving therapy combined with neoadjuvant or adjuvant chemotherapy as well as chemoradiation therapy alone for metastatic disease. Both chemotherapy regimens, those used to treat SCNCL and invasive breast cancer, have been described in these reports.

Conclusion: Primary SCNCB is a very rare type of breast cancer with no standard treatment. Further research is needed to better understand the behavior of this rare tumor in order to develop a standard approach to treatment.

Keywords: Breast; Breast cancer; Case report; Chemotherapy; Small cell neuroendocrine carcinoma.

Fig. 1

Diagnostic mammogram: Right mediolateral oblique view showing an irregular high density mass in the right breast, posterior depth, upper region.

Fig. 2

Ultrasonography of right breast and axilla: Irregular hypoechoic mass in the right axillary tail, resembling carcinoma and highly suggestive of malignancy.

Fig. 3

H&E staining on high power field (40×) showing neoplastic cells with nuclear pleomorphism, nuclear molding, mitotic figures, hyperchromatic nuclei, minimal cytoplasm, and indistinct nuclei consistent with the diagnosis of small cell neuroendocrine carcinoma.

Fig. 4

Immunohistochemical staining for synaptophysin is positive with objective of 40x.

Fig. 5

Breast MRI: 4.6 × 6.6 × 6.3 cm irregular mass in the right axilla with multiple oval masses in the right axillary tail consistent with pathological lymph nodes.