An Unusual Case of Primary Small Cell Neuroendocrine Carcinoma of the Breast

Management of Neuroendocrine Breast Carcinoma (NEBC): Review of Literature

Extra pulmonary high-grade poorly differentiated neuroendocrine carcinomas (EP-NECs) are rare tumors that usually arise in the gastrointestinal and genitourinary tracts. Primary neuroendocrine carcinoma of the breast (NEBC) is extremely rare, representing less than 0.1% of all breast cancers and less than 1% of neuroendocrine neoplasms. Consequently, they can be misdiagnosed as other types of breast cancer, however, proper immunohistochemical (IHC) studies can assist with making the correct diagnosis. Management of NEBC can be challenging given the paucity of evidence-based literature and should not routinely follow the therapeutic guidelines of other breast cancers. In this article, we review the current literature regarding the management of NEBC.

Clinical characteristics and prognosis of primary small cell carcinoma of the breast: a propensity score-matched, population-based study

OBJECTIVE

The purpose of this study was to describe the clinicopathological characteristics and prognosis of primary small cell carcinoma of the breast (PSCCB) and compare PSCCB with breast invasive ductal carcinoma (IDC).

DESIGN

A retrospective cohort study.

SETTING

Data of patients with PSCCB and breast IDC were identified from the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2016.

PARTICIPANTS

Eighty-three patients with PSCCB and 410 699 patients with breast IDC were enrolled in the present cohort study.

MATERIALS AND METHODS

Patients with PSCCB and breast IDC were identified from the SEER database between 2004 and 2016. The clinicopathological characteristics and survival of patients with PSCCB and IDC were compared. Propensity score matching (PSM) analysis was performed to adjust for differences in baseline characteristics when comparing overall survival (OS) and cancer-specific survival (CSS). Moreover, OS-/CSS-specific nomograms were established to predict the prognosis of PSCCB.

RESULTS

Compared with IDC, PSCCB was significantly correlated with older age, male, higher pathological grade, higher TNM (tumour, node, metastases) stage, a higher proportion of triple-negative breast cancer, a lower proportion of ER/PR positivity and significantly worse clinical outcome. The median OS and CSS of patients with PSCCB were 23.0 m (95%CI 13.0 to 56.0) and 28.0 m (95%CI 18.0 to 66.0), respectively. The 5-year OS and CSS rates in the PSCCB group were 36.1% and 42.4%, respectively. In the matched cohort after PSM analysis, patients with PSCCB had significantly worse OS and CSS than IDC patients. Multivariate Cox regression analysis demonstrated that T stage and administration of chemotherapy were independent prognostic factors for both OS and CSS in patients with PSCCB. The C-index for OS-/CSS-specific nomogram was 0.75 (95%CI 0.66 to 0.85)/0.79 (95%CI 0.69 to 0.89), respectively. The calibration curve in the ROC analysis indicated that the predicted value was consistent with the actual observation value. Decision curve analysis suggested that the nomogram model has a significant positive net benefit from the risk of death and are better than the traditional TNM staging system.

CONCLUSION

PSCCB has distinct clinicopathological characteristics, and patients with PSCCB have significantly worse clinical outcomes than those with IDC.

Primary Small Cell Carcinoma of the Breast: An Approach to Medical and Surgical Management

Primary small cell carcinoma of the breast (PSCCB) is a rare and aggressive tumor. Due to the small number of PSCCB cases, there are no established treatment protocols. We report a case of a 55-year-old perimenopausal woman who presented with a palpable left breast mass. A breast mass biopsy was performed, and pathology was consistent with poorly differentiated neuroendocrine small cell carcinoma. Imaging with magnetic resonance imaging (MRI) and positron emission tomography (PET) excluded metastatic disease. Due to recurrent positive margins, the patient underwent two lumpectomies and received neoadjuvant chemotherapy in between procedures. She ultimately underwent a left mastectomy and received postoperative radiation therapy. This case report aims to highlight the challenges that ensue following a diagnosis of PSCCB and underscores the need for creating a standardized treatment model for these vulnerable patients.

Primary Breast Small Cell Carcinoma With Merkel Cell Features: A Case Report and Literature Review

Neuroendocrine carcinoma of the breast is a rare malignant tumor which, with the features of Merkel cells is even rarer. Herein, we report a case of small cell carcinoma with Merkel cell features in a 52-year-old female. Microscopically, the tumor was characterized by diffuse and consistent small round cells that were de-adherent. The tumor cells had round or oval nuclei with delicate chromatin and small nucleoli, the cytoplasm was sparse and eosinophilic. Additionally, the tumor was accompanied by high-grade ductal carcinoma in situ. Immunohistochemical staining showed that infiltrating tumor cells were positive for neuroendocrine markers, and punctately positive for CK20. The patient underwent modified radical mastectomy, axillary lymph node dissection, and postoperative adjuvant chemotherapy. No recurrence or metastasis was observed during follow-up period. Primary breast small cell carcinoma with Merkel cell features is rare and easily misdiagnosed as Merkel cell carcinoma. Early diagnosis and treatment may improve patient prognosis.

Invasive Breast Carcinoma with Neuroendocrine Differentiation: A Single-Center Analysis of Clinical Features and Prognosis

Introduction Invasive breast cancer with neuroendocrine differentiation is a rare subtype of breast malignancy. Due to frequent changes in the definition of these lesions, the correct diagnosis, estimation of exact prevalence, and clinical behaviour of this entity may be challenging. The aim of this study was to evaluate the prevalence, clinical features, and outcomes in a large cohort of patients with breast cancer with neuroendocrine differentiation.

Patients Twenty-seven cases of breast cancer with neuroendocrine differentiation have been included in this analysis. Twenty-one cases were identified by systematic immunohistochemical re-evaluation of 465 breast cancer specimens using the neuroendocrine markers chromogranin A and synaptophysin, resulting in a prevalence of 4.5%. A further six cases were identified by a review of clinical records.

Results Median age at the time of diagnosis was 61 years. 70% of patients had T2 – 4 tumors and 37% were node-positive. The most common immunohistochemical subtype was HR-positive/HER2-negative (85%). 93% were positive for synaptophysin and 48% for chromogranin A. Somatostatin receptor type 2A status was positive in 12 of 24 analyzed tumors (50%). Neuroendocrine-specific treatment with somatostatin analogues was administered in two patients. The 5-year survival rate was 70%.

Conclusions Breast cancer with neuroendocrine differentiation is mostly HR-positive/HER2-negative and the diagnosis is made at a higher TNM stage than in patients with conventional invasive breast carcinoma. Moreover, breast cancer with neuroendocrine differentiation was found to be associated with impaired prognosis in several retrospective trials. Due to somatostatin receptor 2A expression, somatostatin receptor-based imaging can be used and somatostatin receptor-targeted therapy can be offered in selected cases.

Evolution of an invasive ductal carcinoma to a small cell carcinoma of the breast: A case report

RATIONALE

Small cell carcinoma (SCC) is a rare subtype of breast cancer and presents a complex diagnostic and treatment challenge, due to paucity of data. To the best of our knowledge, most cases of breast SCC reported in the literature describe a de novo breast primary. Our case is unique as it describes the evolution of an invasive ductal carcinoma after treatment into a SCC of the breast.

PATIENT CONCERNS AND DIAGNOSIS

We report a case of a 53-year-old female, lifelong non-smoker, who initially presented with breast mass noted on self examination. Breast and axillary lymph node biopsy demonstrated a hormone receptor positive invasive ductal carcinoma with a metastatic T3 lesion.

INTERVENTION

She was treated with first-line palbociclib/letrozole with initial clinical response, and at progression was switched to capecitabine with no response. Repeat biopsy of the axillary lesion showed evolution of the tumor into a triple negative breast cancer. She was then treated with third-line paclitaxel and radiation therapy with good initial response. She eventually had further disease progression and presented with a new mediastinal lymphadenopathy causing SVC syndrome. Biopsy of this showed a small cell variant of breast neuroendocrine carcinoma. Due to the evolution of histology in this case, a retrospective review of her initial breast specimen as well as the second biopsy from the axilla was conducted which confirmed that the mediastinal lymphadenopathy was metastatic from the original breast tumor.

OUTCOMES AND LESSONS

We speculate that the initial treatment allowed a minority of treatment-resistant neuroendocrine cells to grow and become the dominant face of the tumor. Our patient had an excellent response to carboplatin/etoposide and consolidative locoregional radiotherapy but presented with an early intracranial recurrence. This is a similar pattern of metastases as seen in lung SCC and highlights a potential role for prophylactic cranial irradiation in breast SCC. Further studies are needed to better understand the biology and treatment of breast SCC which continues to present a challenge for clinicians.

Primary neuroendocrine carcinomas of the breast and neuroendocrine differentiated breast cancers: Relationship between histopathological and radiological features

PURPOSE

The aim of this study wasto investigate whole-breast imaging findings (mammography, ultrasonography (US), magnetic resonance imaging (MRI),clinical, and histopathological findings of primary neuroendocrine carcinomas of the breast (NEC) and neuroendocrine differentiated breast cancers (NEBC).

METHODS

Patients withadiagnosis of breast cancer with histopathological neuroendocrine features between the years 2010 and 2021 were retrospectively screened.The lesions were divided into two main groups depending on staining with neuroendocrine markers (synaptophysin and chromogranin A). Those showing focal staining were categorized as NEBC while those with diffuse staining as NEC.The mammography, US, and MRI of the lesionswere reviewed in consensus by two breast radiologists in order to assess imaging featuresretrospectively according to the Breast Imaging Reporting and Data System (BI-RADS) 5th lexicon.The findings were compared with breast cancers without neuroendocrine features (BC-WNE) which were randomly selected from the same database.

RESULTS

A total of 105 lesions [NEBC (n = 44), NEC(n = 11), BC-WNE (n = 50)] were evaluated.Patients with neuroendocrine tumors were older (p < 0.001) than those with BC-WNE. Compared with BC-WNE tumors, radiological findings typical of malignancy such as irregular shape [NEBC (7/20); NEC(3/7) vs BC-WNE (35/43); p < 0.001], spiculation [NEBC (2/20); NEC(0/7) vs BC-WNE (21/43); p < 0.001], architectural distortion [(NEBC (3/24); NEC(0/9) vs BC-WNE (31/50); p < 0.001)], calcification [(NEBC (6/24), NEC(0/9) vs BC-WNE (n = 27/50); p = 0.001)] on mamography, non-parallel orientation to skin [(NEBC (n = 17/29), NEC(n = 4/9), BC-WNE (n = 35/42); p = 0.008)], acoustic shadowing [(NEBC (n = 12/29), NEC(1/9), BC-WNE (n = 29/42); p = 0.009)], axillary lymphadenopathy [(NEBC(n = 3/30), NEC(n = 1/9), BC-WNE (21/50); p < 0.001)]on US were less common features of the neuroendocrine carcinomas of breast. Aside from shape features, there was no significant difference in contrast pattern (p = 0.866), kinetic curve (p = 0.454) and diffusion restriction (p = 0.242) on MRI.

CONCLUSION

Characteristic malignant imaging features, including irregular shape, spiculated margins, suspicious calcifications, and posterior acoustic shadowing, are uncommon in neuroendocrine carcinomas of breast. These carcinomas tend to show more benign imaging features when compared with BC-WNE.

Epidemiology, Treatment and Prognosis Analysis of Small Cell Breast Carcinoma: A Population-Based Study

BACKGROUND

Primary small cell breast carcinoma (SCBC) is an uncommon malignancy with highly invasive behavior. The aim of this study was to find out more about the incidence, clinicopathologic characteristics and identify potential prognostic factors of SCBC.

METHODS

Data of patients with primary diagnosis of SCBC between 1975 and 2018 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. The incidence after adjustment for age and percentage change per year in incidence were calculated. Disease-specific survival (DSS) and overall survival (OS) were analyzed among these SCBC patients identified from the SEER database. The whole cohorts were randomized into training and validation cohorts as ratio of 7: 3. Cox regression analysis was performed to determine predictors of survival with the training cohorts. Predictive models were constructed with training cohorts, and nomogram validation was performed using receiver operating characteristic curves, concordance indices and calibration curves in both training and validation cohorts.

RESULTS

323 SCBC patients were enrolled finally during the research period. The overall incidence after adjustment for age between 1990 and 2018 was 0.14 per million per year, and the prevalence of the incidence has plateaued. Most of these tumors were poorly differentiated or undifferentiated. The most prevalent presenting stage was Stage II. Patients identified in this study were randomly divided into training (n = 226) and testing (n = 97) cohorts. Multivariate Cox proportional hazards model showed that chemotherapy, surgery and stage were important predictors of DSS and OS.

CONCLUSION

SCBC is considered an infrequent breast neoplasm with aggressive characteristics. Tumor stage is associated with poor prognosis. Combination of surgery and chemotherapy is the main treatment for SCBC.

Rare case of primary small-cell neuroendocrine breast carcinoma

Small-cell breast cancer is a very rare and aggressive type of neuroendocrine carcinoma. Histologically, it is indistinguishable from small-cell neuroendocrine lung cancer. Due to that, patients with small-cell neuroendocrine breast cancer should undergo examination of other areas of the body. Small-cell breast cancer may be treated with a combination of surgery, radiation therapy and chemotherapy. However, no standard treatment exists due to the small number of cases. We present a case of a 49-year-old woman with right breast primary small-cell neuroendocrine carcinoma.

Neuroendocrine breast carcinoma: a rare but challenging entity

Breast carcinoma with neuroendocrine differentiation, also known as neuroendocrine breast carcinoma (NEBC), includes a heterogeneous group of rare tumors, which account for 2–5% of all invasive breast carcinomas. Because of their low incidence, most of the current limited knowledge of these tumors derives from anecdotal case reports or small retrospective series. The diagnosis of NEBC is based on the presence of morphological features similar to gastrointestinal and lung NETs and neuroendocrine markers. NEBCs are usually hormone receptors positive and HER2 negative, but despite this luminal phenotype, most recent studies suggested that NEBC could be associated with worse prognosis compared to invasive breast cancer without neuroendocrine differentiation. Due to its rarity and lack of randomized data, there is little evidence to guide the choice of treatment, so NEBC is currently treated as any invasive breast carcinoma not-otherwise specified. Recently, attempts to molecularly characterize NEBC have been made, in order to provide new targets for a more personalized treatment of this uncommon entity.

TTF-1 Positive Primary Small Cell Carcinoma of the Breast: A Case Report and Review of the Literature

Primary small cell carcinoma of the breast (SCCB) is a rare tumor subtype comprising <0.1% of all breast carcinomas. Here we present a case of thyroid transcription factor-1 (TTF-1) positive SCCB that recurred within 3 years of diagnosis in the lung and lymph nodes. Given the small number of cases, no clear guidelines exist on the appropriate management of patients with these aggressive tumors. We present a case study and review the current literature to highlight the knowledge gaps and needs of patients with these rare tumors. A 50-year-old premenopausal woman with no family history, presented with a palpable right breast mass. Biopsy was consistent with primary SCCB that was poorly differentiated, positive for synaptophysin and chromogranin and TTF-1 and presence of ductal carcinoma in situ component showing neuroendocrine differentiation. Imaging with PET, CT, and MRI brain excluded any other sites of primary disease. She underwent a right lumpectomy with axillary lymph node dissection and was treated with adjuvant cisplatin-based chemotherapy and concurrent radiation therapy. Thirty-four months later, routine scans showed a new right lower-lobe lung nodule and an enlarged sub-carinal node that was proven to be poorly differentiated neuroendocrine cancer. This case report sheds light on a rarely described disease and provides a comprehensive approach to diagnosis and management. Primary SCCB is an extremely rare, aggressive form of breast cancer that is molecularly and histologically similar to SCLC. However, a review of the literature highlights recent mutational analyses that show important differences between these two cancer types, including an increase in PIK3CA mutations in primary SCCB. Further studies, including genomic analyses are needed to better define this malignancy and to develop a standard treatment.

Primary small cell carcinoma of the breast: a case report

Background

Neuroendocrine breast cancer is a rare entity that was defined in 2003 by the World Health Organization as a separate breast cancer subtype. The diagnosis of neuroendocrine breast cancer requires the presence of neuroendocrine features in at least 50% of malignant cells, the exclusion of non-mammary primary tumors, as well as the presence of an in situ component in breast histology. The treatment and prognosis of neuroendocrine breast cancer are still not well established. Small cell carcinoma of the breast is a subtype of neuroendocrine cancer, resembling small cell carcinoma of the lung. It has a very poor prognosis and warrants treatment with platinum-based chemotherapy.

Case presentation

We herein report the case of a 47-year-old white woman with a left breast mass that was found to be an early-stage, high-grade small cell carcinoma of the breast. Positron emission tomography-computed tomography imaging excluded any other primary disease. Our patient underwent a left total mastectomy with sentinel lymph node biopsy and received cisplatin-based adjuvant chemotherapy. Our patient remains free of disease to date.

Conclusions

This case report sheds light on a rarely described disease and provides a comprehensive approach to diagnosis and management. Neuroendocrine carcinoma of the breast is a well-defined histologic subtype of breast cancer. Small cell carcinoma of the breast is a rare subtype of neuroendocrine breast cancer. Due to the rarity of this entity, prognosis has still not been well established, and treatment has not been standardized, cisplatin-based treatment has been used in this case similar to small cell carcinoma of the lung.

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

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Primary small cell neuroendocrine carcinoma of the breast is a very rare diagnosis.

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It has similar features to small cell neuroendocrine carcinoma of the lung.

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Diagnostic workup must exclude metastasis from another primary site.

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Treatment combines approaches for more common types of lung and breast cancer.

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Further studies are needed to standardized the treatment for primary SCNCB.

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.

Primary neuroendocrine carcinoma of the breast: clinical, imaging, and histologic features

OBJECTIVE

The purpose of this study was to evaluate the clinical, imaging, and histopathologic findings of primary neuroendocrine carcinoma of the breast.

MATERIALS AND METHODS

A pathology database was searched for the records of patients with a histopathologic diagnosis of primary neuroendocrine carcinoma of the breast who had undergone mammography, sonography, or MRI between 1984 and 2011. The imaging studies of eligible patients were retrospectively reviewed according to the BI-RADS lexicon, and clinical presentation and histopathologic characteristics were documented. Imaging characteristics were compared with historical controls of invasive mammary carcinoma.

RESULTS

Eighty-seven patients (84 women, three men; mean age, 62.9 years; range, 28-89 years) were included in the study. The mean tumor size was 3.1 cm (range, 0.6-11 cm). Sixty-five of 84 (77.4%) cancers were estrogen and progesterone receptor positive and ERBB2 negative. A palpable mass (55.8%) was a common clinical manifestation. A high-density, round or oval, or lobular mass with nonspiculated margins on mammograms and an irregular (65.4%), hypoechoic (78.4%) mass, with indistinct margins (43.5%), no or enhanced posterior acoustic features (77.9%) on sonograms were common findings. MRI revealed an irregular mass (83.3%), irregular margins (63.6%), and washout kinetics (85.7%). Neuroendocrine carcinoma presented more frequently as masses on mammograms. Calcifications were infrequent compared with their occurrence in invasive mammary cancer.

CONCLUSION

Primary neuroendocrine carcinoma of the breast has mammographic features that differ from those of invasive mammary carcinoma. A round, oval, or lobular mass with nonspiculated margins, positive estrogen and progesterone receptor results, and negative ERBB2 results should raise suspicion of primary neuroendocrine carcinoma.

Primary neuroendocrine carcinoma of the breast: radiologic and pathologic correlation

Primary neuroendocrine carcinoma of the breast (PNCB) is a rare type of breast cancer. There have been few reports on PNCB and radiologic-pathologic correlation in PNCB has not been described thoroughly. We present a rare case of pathologically confirmed poorly differentiated PNCB removed via lumpectomy. Image findings on mammography, ultrasonography, computed tomography, magnetic resonance image, and positron emission tomography-computed tomography are also presented.

Neuroendocrine differentiation correlates with hormone receptor expression and decreased survival in patients with invasive breast carcinoma

AIMS

Invasive breast carcinoma (IBC) with neuroendocrine (NE) differentiation has been controversial in terms of its definition and clinical outcome. We investigated the incidence and clinical significance of NE differentiation in patients with IBC.

METHODS AND RESULTS

We performed immunohistochemistry for NE markers, chromogranin-A and synaptophysin on 1428 IBC samples using tissue microarrays and classified cases with NE differentiation into two groups, focal (1-49% tumour cells positive for any NE marker) and diffuse (≥50% tumour cells positive) groups. Fifty-nine cases (4.1%) showed NE differentiation immunohistochemically, and the majority did not show typical NE morphology. The presence of NE differentiation showed a significant association with positive oestrogen receptor (P = 0.001) and progesterone receptor (P = 0.008) status. Patients with NE differentiation showed worse overall survival (OS) and disease-free survival (DFS) than those without NE differentiation in both univariate (P < 0.001 for both) and multivariate (OS, P = 0.004; DFS, P < 0.001) analyses.

CONCLUSIONS

IBC with NE differentiation is a distinct subtype of mammary carcinoma with an aggressive clinical outcome.

A Case of Small Cell Cancer of the Breast in a Male with Synchronous Stage IV Non-Small Cell Lung Carcinoma

Extrapulmonary small cell carcinomas (EPSCC) are extremely rare. Most reports indicate success with therapy directed at the tumor as if it was pulmonary small cell carcinoma Primary small cell carcinoma of the breast is an uncommon form of EPSCC. Differentiating between a primary small cell carcinoma of the breast from metastatic disease to the breast is very important. According to the literature, there have been approximately 70 cases reported worldwide. Of these cases, only two cases are documented in men. Prognosis is varied and depends on stage of disease at presentation. A combination of surgery, chemotherapy and/or radiation is required to adequately treat patients with small cell carcinoma of the breast. We present a case of a male patient diagnosed with stage IV non-small cell lung carcinoma first and then subsequently diagnosed with a concurrent small cell carcinoma of the breast responding to treatment with concurrent chemotherapy and radiation.

Locally-advanced primary neuroendocrine carcinoma of the breast: case report and review of the literature

Background

Primary neuroendocrine carcinoma of the breast is a heterogeneous group of rare tumors with positive immunoreactivity to neuroendocrine markers in at least 50% of cells. Diagnosis also requires that other primary sites be ruled out and that the same tumor show histological evidence of a breast in situ component. Primary neuroendocrine carcinoma of the breast rarely presents as locally advanced disease and less frequently with such widespread metastatic disease as described herein. The review accompanying this case report is the first to provide an overview of all the cases of primary neuroendocrine carcinoma of the breast published in the literature and encompasses detailed information regarding epidemiology, histogenesis, clinical and histologic diagnosis criteria, classification, surgical and adjuvant treatment, as well as prognosis. We also provide recommendations for common clinical and histologic pitfalls associated with this tumor.

Case presentation

We describe a case of a 51-year-old Hispanic woman initially diagnosed with locally-advanced invasive ductal carcinoma that did not respond to neodjuvant treatment. After undergoing modified radical mastectomy the final surgical pathology showed evidence of alveolar-type primary neuroendocrine carcinoma of the breast. The patient was treated with cisplatin/etoposide followed by paclitaxel/carboplatinum. Thirteen months after surgery the patient is alive, but developed pulmonary, bone, and hepatic metastasis.

Conclusion

The breast in situ component of primary neuroendocrine carcinoma of the breast may prevail on a core biopsy samples increasing the probability of underdiagnosing this tumor preoperatively. Being aware of the existence of this disease allows for timely diagnosis and management. Optimal treatment requires simultaneous consideration of both the neuroendocrine and breast in situ tumor features.

Metastatic small cell neuroendocrine carcinoma of the breast

Cutaneous metastases from internal malignancies in women overwhelmingly emanate from the breast and typically exhibit features of an adenocarcinoma, although other histopathologic patterns may also be seen. Neuroendocrine breast carcinoma represents an uncommon variant of mammary carcinoma with fewer than 40 cases of the small cell subcategory reported. As with other small cell carcinomas, they may exhibit Merkel cell-like features and appropriate diagnosis of these tumor deposits often turns on clinical history and an appropriate immunohistochemical profile. Herein, we report the first known patient with cutaneous metastases from a small cell neuroendocrine breast carcinoma.