title: E-cadherin-negative primary small cell carcinoma of the breast. Report of a case and review of the literature.
abstract: Primary small cell carcinoma of the breast is exceedingly rare, with fewer than 25 reported cases. The case presented herein is that of a 61-year-old woman with a 2.5-cm mass of the left breast. She underwent mastectomy with axillary node dissection. Histologic examination revealed sheets and nests of small, hyperchromatic, malignant cells with indistinct nucleoli and scant cytoplasm. High-grade solid and comedo ductal carcinoma in situ also was present. Two of 5 axillary lymph nodes contained metastatic disease. Immunohistochemical analysis demonstrated weak immunoreactivity for cytokeratin, neuron-specific enolase, and bcl-2. This histologic and immunohistochemical profile was consistent with that of a primary small cell carcinoma. Interestingly, this neoplasm lacked immunoreactivity for E-cadherin. E-cadherin expression has been documented in all 11 (100%) of 11 previously reported cases of primary small cell carcinoma of the breast, suggesting that this tumor is a form of ductal carcinoma. To our knowledge, this is the first reported case of E-cadherin-negative small cell carcinoma of the breast, which raises the question of a possible lobular histogenesis in some of these neoplasms.
authors.affiliation: Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
authors.forename: Simon
authors.initials: S
authors.lastname: Bergman
authors.forename: Syed A
authors.initials: SA
authors.lastname: Hoda
authors.forename: Kim R
authors.initials: KR
authors.lastname: Geisinger
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Creager
authors.forename: Jacqueline K
authors.initials: JK
authors.lastname: Trupiano
mesh_terms: D014408:Biomarkers, Tumor; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D015820:Cadherins / Q000378:metabolism*; D002278:Carcinoma in Situ / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000378:metabolism / Q000473:pathology; D018288:Carcinoma, Small Cell / Q000378:metabolism* / Q000556:secondary; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000378:metabolism; D008197:Lymph Node Excision; D008875:Middle Aged; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D015820:Cadherins; D019253:Proto-Oncogene Proteins c-bcl-2; D007633:Keratins; D010751:Phosphopyruvate Hydratase