Primary oat cell (neuroendocrine) carcinoma of the breast. Report of four cases

Non-metastatic primary neuroendocrine neoplasms of the breast: a reference cancer center's experience of a heterogenous entity

Background

Primary neuroendocrine neoplasms of the breast (Br-NENs) are rare. The classification has been updated in recent years making interpretation of the data published challenging. It is unclear whether neuroendocrine differentiation is associated with poorer prognosis and what treatment approaches should be applied.

Methods

The database for breast cancer patients treated between 2009 and 2022 at the Maria Sklodowska-Curie National Research Institute of Oncology Branch Krakow was explored to search for Br-NENs. Patients' medical and pathological data were collected and analyzed.

Results

We included 22 females with Br-NEN without metastases at the time of diagnosis. The median age was 64 years (range: 28-88), Of the cases, 18 were hormone receptor positive, all were HER-2 negative, the median Ki67 was 27% (10-100%). The median tumor size at the time of diagnosis was 29.5mm (7-75mm), 9 patients were N-positive. DCIS was present in 5 cases. Only one case was negative for chromogranin and synaptophysin staining, but data were missing for 4 cases. Nine patients received adjuvant chemotherapy, mainly based on anthracyclines and taxanes, while 16 received adjuvant hormonal therapy and 15 received postoperative radiotherapy. Radical surgery was performed in all patients, but two underwent suboptimal tumorectomy. One patient had local recurrence, three experienced metastatic disease, all involving the lungs, but these patients are still alive. The median follow-up was 96 months (8-153). Two patients died, with a follow up time of no recurrence >4 years. Our results were compared to twelve case series collecting clinical data on Br-NENs, with median patient number of 10.5 (range: 3-142).

Conclusion

Br-NENs represent a heterogenous group of diseases, lacking data from prospective studies or clinical trials. There are no established treatment standards tailored for Br-NENs. Our patients' cohort exhibited a favorable prognosis, potentially attributed to lower tumor stage and Ki67 index compared to other reported case series. We suggest that radical surgery and postoperative radiotherapy be administered akin to standard treatment for breast cancer of no special type. ESMO also advocates for this approach in systemic treatment, although we recommend considering platinum-based chemotherapy for patients with poorly differentiated Br-NENs exhibiting high Ki67.

Primary neuroendocrine carcinoma of the breast with leptomeninges metastasis: A case report and literature review

Primary neuroendocrine carcinoma of the breast (NECB) is a rare tumour with an incident rate of 0.3-0.5%. The most common metastatic sites of NECB are liver, bones, lung, pancreas, soft tissues and brain, while leptomeninges metastasis (LM) is reported rarely. This current case report describes a 50-year-old female patient with NECB and LM whose overall survival was 2 months. The report also presents the current literature regarding the knowledge of this unusual tumour and metastatic type. The current patient was diagnosed with NECB with right cerebellar metastasis, followed by LM. She underwent modified radical mastectomy of the left breast, left whole breast radiation therapy and incomplete adjuvant chemotherapy until the metastasis occurred. Whole-brain radiation therapy and a first-line salvage regimen of etoposide and cis-platinum were then undertaken. The patient died 2 months after their LM diagnosis. Primary NECB with LM is sporadic, devoid of effective treatment and associated with a poor prognosis. Consequently, it is vitally important to identify LM in order to achieve longer patient survival.

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.

Genetic and immunohistochemical profiling of small cell and large cell neuroendocrine carcinomas of the breast

Neuroendocrine carcinomas (NEC) of the breast are exceedingly rare tumors, which are classified in the WHO system as small cell (SCNEC) and large cell (LCNEC) carcinoma based on indistinguishable features from their lung counterparts. In contrast to lung and enteropancreatic NEC, the genomics of breast NEC have not been well-characterized. In this study, we examined the clinicopathologic, immunohistochemical, and genetic features of 13 breast NEC (7 SCNEC, 4 LCNEC, 2 NEC with ambiguous small versus large cell morphology [ANEC]). Co-alterations of TP53 and RB1 were identified in 86% (6/7) SCNEC, 100% (2/2) ANEC, and 50% (2/4) LCNEC. The one SCNEC without TP53/RB1 alteration had other p53 pathway aberrations (MDM2 and MDM4 amplification) and was immunohistochemically RB negative. PIK3CA/PTEN pathway alterations and ZNF703 amplifications were each identified in 46% (6/13) NEC. Two tumors (1 SCNEC, 1 LCNEC) were CDH1 mutated. By immunohistochemistry, 100% SCNEC (6/6) and ANEC (2/2) and 50% (2/4) LCNEC (83% NEC) showed RB loss, compared to 0% (0/8) grade 3 neuroendocrine tumors (NET) (p < 0.001) and 38% (36/95) grade 3 invasive ductal carcinomas of no special type (IDC-NST) (p = 0.004). NEC were also more often p53 aberrant (60% vs 0%, p = 0.013), ER negative (69% vs 0%, p = 0.005), and GATA3 negative (67% vs 0%, p = 0.013) than grade 3 NET. Two mixed NEC had IDC-NST components, and 69% (9/13) of tumors were associated with carcinoma in situ (6 neuroendocrine DCIS, 2 non-neuroendocrine DCIS, 1 non-neuroendocrine LCIS). NEC and IDC-NST components of mixed tumors were clonally related and immunophenotypically distinct, lacking ER and GATA3 expression in NEC relative to IDC-NST, with RB loss only in NEC of one ANEC. The findings provide insight into the pathogenesis of breast NEC, underscore their classification as a distinct tumor type, and highlight genetic similarities to extramammary NEC, including highly prevalent p53/RB pathway aberrations in SCNEC.

Primary Small Cell Malignancies of the Breast: Are They Rare Malignancies?

In contrast with the other organs such as the lung, small cell tumors have been less studied in the breast due to their relatively less frequency. Although rare, neuroendocrine neoplasms, some lymphomas, and some small cell sarcomas such as undifferentiated small round cell sarcoma and rhabdomyosarcoma can be seen in small cell morphology in the breast. Many cytological specimens such as fine-needle aspiration biopsies and touch imprint cytology are used for diagnosis and further prognostic/predictive marker determination in primary breast masses, sentinel and axillary lymph nodes, and metastatic masses. Lobular carcinoma deserves to be considered in the small cell tumor group because of its small, monomorphic, discohesive, scant cytoplasmic cytological features. Since so many different types of tumors in the breast can have small cell characteristics, they should be divided into small cell neuroendocrine tumors and small cell nonneuroendocrine tumors. When evaluating small cell breast tumors cytologically, wide tumor diversity should be kept in mind, and clinical, hematological, and radiological features should be taken into consideration.

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.

Histopathology and Cytopathology of Neuroendocrine Tumors and Carcinomas of the Breast: A Review

Neuroendocrine tumors (NET) and carcinomas (NEC) of the breast are rare diseases, but NEC has attracted attention in both cytopathology and surgical pathology because of its specific management and prognosis. Fine-needle aspiration biopsy (FNAB) cytology can make the diagnosis in many cases particularly with high-grade NEC, with definitive diagnosis based on histopathology and immunohistochemistry. This review describes the characteristics of the disease based on the WHO classification 2012 and recent literature and -includes discussion related to the International Academy of Cytology Yokohama System of Reporting Breast FNAB -cytology.

Extrapulmonary Small Cell Carcinoma: Multimodality Treatment Results

Aims and Background

Extrapulmonary small cell carcinoma is a distinct entity that can occur in many sites, and it is pathologically similar to small-cell lung cancer. We report the results of a retrospective study of a multimodality treatment of 16 consecutive patients with a diagnosis of extrapulmonary small-cell carcinoma.

Methods

Primary tumor site was prostate in 2, gallbladder in 2, uterine cervix in 2, liver in 2, endometrium in 1, epididymis in 1, colon in 1, larynx in 1, breast in 1, and unknown primary tumor in 3 patients. Patients’ ages ranged from 19 to 79 years (median, 62). Nine patients had limited and 7 had extensive disease. Histologically, 14 were pure extrapulmonary small-cell carcinoma and 2 were mixed with squamous-cell carcinoma.

Results

Curative surgery was attempted in 8 patients. Seven patients received local-regional adjuvant radiotherapy. All patients, except the one with a breast primary, were treated with chemotherapy (mostly platinum-based regimens). Overall survival for all patients was 41% and 11% at 2 and 5 years, respectively (median survival, 14 months). Median survival for patients with limited disease was 25 months compared to 12 months for patients with extensive disease (P = 0.05).

Conclusions

Treatment results for extrapulmonary small-cell carcinoma are comparable to those of small-cell carcinomas of the lung. Extent of disease is a significant prognostic factor for survival.

Primary Neuroendocrine Carcinoma of the Breast: A Case Report

Primary neuroendocrine carcinoma of the breast is an extremely rare tumor. We present our experience of primary neuroendocrine carcinoma of the breast in a 76-year-old woman. Surgical biopsies from breast and axillary lymphadenopathy showed a neuroendocrine carcinoma. Immunohistochemical staining of tumor cells with GCDFP15, NSE and chromogranin were positive. Computed tomography scans of the chest and abdomen showed no lesion for metastasis or another primary origin. Adjuvant hormone therapy was given, since the tumor was immunohistochemically receptor positive.

Primary small cell carcinoma of the breast: Report of seven cases and review of the literature

Aims and background

The aim of the study was to analyze the clinicopathological characteristics, treatment modalities, and clinical outcome of patients with primary small cell carcinoma of the breast.

Methods

Fifty-three cases of primary small cell carcinoma of the breast were identified; 7 cases in this series and 46 from the English-language medical literature.

Results

There were 52 females and 1 male. The mean age was 53 years. Tumor size ranged from 1 to 18 cm (mean, 4.53). Axillary node metastasis was present in 61.7%. Only one patient had distant metastases at presentation. The presence of hormone receptors was reported in 24.5% of the tumors. Modified radical mastectomy was the most common surgical procedure and was performed in 50.9% of the patients. Adjuvant radiotherapy was administered to 39.6% of the patients, and 69.8% underwent chemotherapy. Thirteen percent of patients received adjuvant tamoxifen therapy. The mean follow-up was 20.75 months (range, 3–60), and 10 of 53 cases (18.9%) died of metastatic disease.

Conclusions

The prognosis of primary small cell carcinoma of the breast largely depends on the initial stage of the disease. Multimodality treatment including surgery, radiotherapy and chemotherapy seems to be the most appropriate strategy for early disease. Chemotherapy is usually unsuccessful in treating metastatic disease.

Papillary and neuroendocrine breast lesions: the WHO stance

In this review, we highlight adaptations in the WHO 2012 classification of papillary and neuroendocrine breast lesions as compared with the previous 2003 version. Consensus criteria for distinguishing atypical ductal hyperplasia from ductal carcinoma in situ within an intraductal papilloma are proposed. The absence of myoepithelial cells around the wall of an encapsulated papillary carcinoma, although raising consideration of an indolent tumour with minimal invasion, is currently regarded as in-situ disease for staging purposes. The majority of solid papillary carcinomas are classified as in-situ tumours, but lesions with irregular tumour islands within desmoplastic stroma may be considered to be invasive. The diagnosis of solid papillary carcinoma without further qualification as either in-situ or invasive disease is discouraged. When invasive papillary carcinoma is seen in the breast, metastatic papillary carcinoma from other organ sites needs to be excluded. WHO 2012 classifies neuroendocrine breast tumours as well-differentiated neuroendocrine tumour, small-cell carcinoma, and invasive breast carcinoma with neuroendocrine differentiation. There is currently no clinical impact of identifying neuroendocrine differentiation in conventional invasive breast carcinomas, apart from acknowledging its frequent occurrence in subtypes such as the hypercellular variant of mucinous carcinoma and solid papillary carcinoma.

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.

Working formulation of neuroendocrine tumors of the skin and breast

In the skin and breast, endocrine tumors are composed of a heterogeneous mixture of endocrine and exocrine cells. The definition of "pure" endocrine carcinomas is a matter for debate, and as a consequence, there is lack of uniform diagnostic criteria. There are no significant clinical differences in either overall or disease-free survival between matched neoplasms with endocrine and without endocrine differentiation nor between the degree of endocrine differentiation and tumor size, stage, or prevalence of vascular invasion for both sites (skin and breast). Here, endocrine tumors of the skin and breast are grouped respectively into three categories that include most of the neuroendocrine tumors of the skin and breast as seen in routine practice. It was felt that the number of different types of neuroendocrine tumors is so conspicuous that it is impossible to organize them in an orderly classification. It has been proposed therefore, for practical diagnostic routine purposes, to arrange these neoplasms into a working formulation. The latter includes heterogeneous lesions respectively of the skin and breast within the same group that have clinical features in common.

Primary small-cell neuroendocrine carcinoma of the male breast: a rare case report with review of the literature

In this case study and review, we present a case of a primary small-cell neuroendocrine carcinoma (SCNC) of the male breast. Primary SCNC of the breast is a rare tumor with less than 30 cases reported in the literature. Most cases are found in women. Another exceptional point is that human epidermal growth factor receptor-2 (Her-2) immunoreactivity was positive in our recent case, which differed to previous reports detailing SCNC in women. We have no evidence to demonstrate the differences between treatment and prognoses for males and females, because we do not have sufficient cases to undertake an evidence-based investigation. We provide this rare case history; review the literature on SCNC of the breast; and discuss detailed information regarding epidemiology, histogenesis, clinical and histologic diagnosis criteria, surgical and adjuvant treatment, and prognosis.

Primary neuroendocrine carcinoma of breast: a rare case report

Primary neuroendocrine carcinoma (PNEC) of breast was an unknown pathologic entity till recently due its rare incidence and lack of definitive criteria for diagnosis. We present a case of PNEC of breast in a middle aged lady. A 34 years lady presented with a breast lump since 1 month, who underwent modified radical mastectomy with axillary clearance. Histopathological diagnoses were infiltrating ductal carcinoma-neuroendocrine (NE) type. Immunohistochemistry showed estrogen, progesterone positivity and NE markers positivity in more than 50% of tumor cells for chromogranin, synaptophysin, neuron specific enolase. On further investigation by whole body computed tomography and magnetic resonance imaging revealed no extra mammary primary tumor. Hence the diagnosis of PNEC of breast was confirmed. Patient received chemo and hormonal therapy and doing well after 6 months of follow up.

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.

Clinical features and treatment response of solid neuroendocrine breast carcinoma to adjuvant chemotherapy and endocrine therapy

Solid neuroendocrine breast carcinoma (solid NEBC) is a relatively uncommon malignant tumor of the breast. The purpose of our study was to explore the incidence and clinical features of this tumor, and to evaluate the efficacy of adjuvant chemotherapy and endocrine therapy for patients with solid NEBC. Of 7542 breast cancers registered during the period from March 2004 to April 2011, 22 patients (0.29%) who underwent surgery had tumors that were histologically confirmed as solid NEBC, and were enrolled in this study. The age range of these patients was 29-77 years (mean 52.5 years). Patients were staged according to the 7th edition of the pathologic tumor-node-metastasis (pTNM) staging system. Biopsies or resection specimens were reviewed and reclassified according to the World Health Organization (WHO) 2003 classification. We recorded clinical features including gender and age, chief complaint, and past medical history, tumor characteristics including size, location, preoperative diagnosis, and pathologic and immunohistochemical findings, the therapeutic schedule, and the follow-up results. Solid NEBC is a rare and distinct category of malignant disease of the breast, with good prognosis, and in most early-stage cases, is resectable. The role of adjuvant chemotherapy and endocrine therapy in solid NEBC may be limited and should be studied further.

[Primitive mammary neuroendocrine tumor: about a rare case]

Les carcinomes neuroendocrine primitifs du sein sont des tumeurs rares et représentent 2 à 5% des cancers mammaires. Nous rapportons le cas de localisation mammaire chez une patiente de 50 ans. Il s'agit d'une tumeur classée T4d N1 M0. La tumeur est suspecte radiologiquement. Une microbiopsie est réalisée. L’étude anatomopathologique et immunohistochimique est en faveur d'une tumeur neuroendocrine primitive du sein à grande cellules exprimant les récepteurs progestéroniques seulement. Vu le caractère inflammatoire de la tumeur une chimiothérapie est démarrée avec bonne évolution clinique. A la fin de la chimiothérapie on prévoit de réaliser une mastectomie avec curage axillaire et en fonction des résultats définitifs, une radiothérapie. Une hormonothérapie sera envisagée une 2ème étude immunohistochimique sur la pièce de mastectomie. Vu la rareté des carcinomes neuroendocrines mammaires primitifs, il n'existe pas de standard thérapeutique et le pronostic demeure difficile à déterminer.

Less Common Variants and Mimics of DCIS

The purpose of this review is to discuss the less common variants and mimics of ductal carcinoma in situ (DCIS). DCIS lesions are heterogeneous in clinical presentation and behavior, morphology, biomarker profile, and identified genetic aberrations. DCIS is most easily recognized when presenting with classical features. The diagnosis is more challenging when a lesion displays less common cytologic features and has architectural patterns that overlap with other benign or malignant entities.

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.

Does hormonal therapy have a therapeutic role in metastatic primary small cell neuroendocrine breast carcinoma? Case report and literature review

Primary neuroendocrine carcinoma of breast (NECB) is a very rare tumor; the World Health Organization(WHO) subcategorized these tumors into 3 major histologic subtypes: solid, small cell carcinoma (SMCC), and large cell NE carcinoma. The SMCC subtype is the least common and most aggressive and has been reported to be as aggressive as its pulmonary counterpart. SMCC is usually confirmed based on clinical, pathologic,and imaging studies. Local disease is usually managed in a fashion similar to that of the usual ductal breast cancer; in the metastatic SMCC setting, regimens that are implemented in small cell lung cancer are usually attempted, according to case reports and published small case series. Hormone receptors can be expressed in more than 90% of the solid tumor subtype; however its expression is manifested in about 50% of cases of SMCC. Although hormonal therapy can be used successfully to treat the usual metastatic ductal breast cancer,its utility in metastatic SMCC has not been reported. We report an impressive response to hormonal therapy in a patient with late relapse of breast carcinoma with a metastatic SMCC subtype that expressed hormone receptors. The response to hormonal therapy was sustained for about 12 months. The response to hormonal therapy is definitely an interesting finding that, to our knowledge, has not been described before in the setting of metastatic SMCC. We suggest considering adding hormonal therapy to the treatment pipeline for primary SMCC of the breast that express hormone receptors.

Small-cell neuroendocrine carcinoma of the breast

A small-cell carcinoma is one of the histologic subtypes of primary neuroendocrine carcinomas of the breast. A small-cell carcinoma is a rare entity of the breast and exhibits similar morphologic features as neuroendocrine tumors of the gastrointestinal tract and lung. We present the imaging and pathologic findings of a primary small-cell neuroendocrine carcinoma of the breast. This is the first report of a primary small-cell carcinoma arising from the breast in Korea.

Bilateral primary breast neuroendocrine carcinoma in a young woman: report of a case

Bilateral breast carcinoma accounts for approximately 5% of all patients with breast cancer, while neuroendocrine breast carcinomas comprise less than 5% of invasive breast carcinomas. In addition, most patients with breast neuroendocrine carcinomas are older. Therefore, bilateral primary breast neuroendocrine carcinoma at a young age is extremely rare. We herein report bilateral neuroendocrine carcinoma of the breast in a 29-year-old woman who underwent bilateral lumpectomy with the initial symptom of bilateral nipple discharge. Grossly, the lesions in both breasts were masses with infinite margins. Histologically, this case was consistent with primary neuroendocrine carcinoma arising in bilateral breasts. Cells from both breast tumors were positive for chromogranin A, neuron-specific enolase, synaptophysin, cytokeratin 7, estrogen receptor, and progesterone receptor, and negative for Her2, cytokeratin 34β12, cytokeratin 5/6, smooth muscle actin, p63, S-100 protein, and p53. The Ki67 and NE proliferative indices were below 1%. To the best of our knowledge, this is the first reported case in China of bilateral primary neuroendocrine carcinoma presenting in a young woman.

Small cell neuroendocrine tumor of the breast in a 40 year-old woman: a case report

INTRODUCTION

Small cell neuroendocrine cancer of the breast is a rare tumor with less than 30 cases reported in the literature. The morphological and immunohistochemical patterns of this tumor are similar to small cell neuroendocrine cancer of the lung. For this reason, it is often difficult to distinguish a primary small cell neuroendocrine cancer of the breast from a metastatic lesion from other sites.

CASE PRESENTATION

We report and characterize with immunohistochemical techniques a case of primary small cell neuroendocrine cancer of the breast occurring in a 40-year-old Caucasian woman. A palpable and mobile 3.0 cm tumor was located in the upper-outer quadrant of her right breast. Lumpectomy and subsequent radical mastectomy with axillary lymph node resection were performed. Microscopically, the tumor consisted predominantly of a diffuse proliferation of small oat cells. The tumor cells were positive for neuroendocrine markers chromogranin A and synaptophysin. One of 16 lymph nodes was metastatic. A correct treatment needs to be chosen.

CONCLUSIONS

It has recently been demonstrated that early small cell neuroendocrine cancer of the breast shows a good prognosis with adjuvant treatments with high disease free survival. Our patient is alive and well without disease eight years after treatment. We performed an adjuvant therapy with the classic scheme doxorubicin and cyclophosphamide, followed by carboplatin and etoposide. A more extensive review is required to define a standard treatment protocol for this rare neoplasm.

Neuroendocrine differentiation in breast cancer: established facts and unresolved problems

Neuroendocrine breast carcinoma (NEBC) diagnosis relies on (i) presence of morphologic neuroendocrine features, and (ii) neuroendocrine markers expressed in more than 50% of tumor cells. The World Health Organization classification describes 3 main histologic types: the solid, the small/oat cell, and the large cell variant. In addition, we have recently proposed a further categorization into 5 subgroups: the first 3 categories encompass solid lesions and include (i) solid cohesive carcinomas, (ii) alveolar carcinomas, and (iii) small cell carcinoma; the last subgroups include mucin-producing tumors which are (iv) solid papillary carcinomas and (v) cellular mucinous carcinomas. Chromogranin A and synaptophysin have been considered as the most sensitive and specific neuroendocrine markers in NEBC. At the molecular level, recent gene expression profiling studies have shown that NEBCs pertain to the luminal molecular type, being positive for hormone receptors and negative for HER2. Moreover, it has been demonstrated that mucinous and neuroendocrine carcinomas are transcriptionally distinct from conventional invasive ductal carcinomas. Following the above criteria, NEBCs constitute approximately 1% of all breast carcinomas. The clinical effect of neuroendocrine breast cancer is still a matter of debate; however, when compared with unselected breast cancers, NEBCs show a less aggressive clinical behavior.

Mucinous and neuroendocrine breast carcinomas are transcriptionally distinct from invasive ductal carcinomas of no special type

Mucinous carcinoma is considered a distinct pathological entity. However, mucinous tumours can be divided into a least two groups: mucinous A (or paucicellular) and mucinous B (or hypercellular). Mucinous B cancers display histological features that significantly overlap with those of neuroendocrine carcinomas. We investigate using genome-wide oligonucleotide microarrays whether mucinous A, mucinous B and neuroendocrine carcinomas are entities distinct from histological grade- and molecular subtype-matched invasive ductal carcinomas of no special type. Mucinous A and B and five neuroendocrine carcinomas were of luminal A subtype, whereas one neuroendocrine tumour was of luminal B phenotype. When analysed in conjunction with grade- and molecular subtype-matched invasive ductal carcinomas, hierarchical clustering analysis showed that the majority of mucinous and neuroendocrine cancers formed a separate cluster. Significance analysis of microarrays identified 3155 genes differentially expressed between mucinous/ neuroendocrine carcinomas and grade- and molecular subtype-matched invasive ductal carcinomas (false discovery rate <0.85%), and revealed that genes associated with connective tissue/extracellular matrix were downregulated in mucinous/neuroendocrine cancers compared to invasive ductal carcinomas. When subjected to hierarchical clustering analysis separately, mucinous A cancers formed a discrete subgroup, whereas no separation was observed between mucinous B and neuroendocrine cancers. In fact, significance of microarray analysis showed no transcriptomic differences between mucinous B and neuroendocrine cancers, whereas mucinous A cancers displayed 89 up- and 26 downregulated genes when compared with mucinous B (false discovery rate <1.15%) and 368 up- and 48 downregulated genes when compared to neuroendocrine carcinomas (false discovery rate <1.0%). Our results provide circumstantial evidence to suggest that mucinous and neuroendocrine carcinomas are transcriptionally distinct from histological grade- and molecular subtype-matched invasive ductal carcinomas, and that luminal A breast cancers are a heterogeneous group of tumours. These findings support the contention that mucinous B and neuroendocrine carcinomas are part of a spectrum of lesions, whereas mucinous A is a discrete entity.

Neuroendocrine Carcinoma of the Breast: Case Report and Literature Review

Background

Neuroendocrine carcinoma of the breast is a rare disease.

Case Report

We present a 65-yearold female patient with an enlarged breast mass within 2 months. Solid neuroendocrine carcinoma of the breast was diagnosed by excision biopsy and histopathological analysis. A lumpectomy with the right axillary sentinel lymph node biopsy was performed, and the mass was completely resected. The literature on neuroendocrine carcinoma of the breast is reviewed.

Conclusion

Due to the diversity of imaging findings from primary breast neuroendocrine carcinomas, the diagnosis is based on immunohistochemical staining of neuroendocrine markers. Surgery has turned out to be the first-line treatment and subsequently radiation may play a role in palliative treatment.

Primary mammary small-cell carcinoma: A case report and review of the literature

Only a few cases of primary small-cell carcinoma of the breast have been documented in the current medical literature. A confident diagnosis can only be made if a nonmammary site is excluded or if an in-situ component can be demonstrated histologically. These criteria have been met only in a very few of the published cases, including this case report. We describe a case of a 68-year-old lady with left breast lump, which was diagnosed as breast cancer on fine-needle aspiration and core biopsy. Metastatic workup was negative for disease elsewhere, and she received 3 cycles of neoadjuvant chemotherapy followed by surgery (modified radical mastectomy). However, the disease behaved very aggressively in the postoperative period. There is a lack of consensus regarding the management of the primary tumor. Present surgical treatment options are similar to those in cases of invasive ductal breast cancer, as appropriate for the size and stage of the lesion. A review of current literature on his rare entity is also presented.

Radiolabelled somatostatin analogs for diagnosis and radio-guided surgery of neuroendocrine breast cancer undetectable with conventional imaging procedures

Some neoplasms are classified as primary neuroendocrine tumours (NETs) because of their positivity for neuroendocrine markers [chromogranins A and B (CgA, CgB) and neuron-specific enolase (NSE)]. Neuroendocrine differentiation has been reported, for example, in both "in situ" and infiltrating breast cancer. Diagnosis of NET is bio-humoral (CgA, NSE, synaptophysin) and instrumental. Even if the final diagnosis is made by open biopsy, radionuclide imaging using radiolabelled somatostatin analogs, such as In-111 pentetreotide, may detect neuroendocrine primary tumours and metastases before they become detectable using traditional and advanced imaging modalities [mammography (MX), ultrasound (US) and magnetic resonance imaging (MRI)]. When neuroendocrine breast lesions are not detectable, radio-guided surgery (RGS) is able to localise cancer. We report a case of a woman with a palpable lymph node in the left axilla. She underwent a US-guided lymph node biopsy, which was positive for massive metastases, probably of neuroendocrine breast origin. Mammary plus axillary US showed only lymphadenopathy in the left axilla. MX and breast MRI were negative. Neoplastic markers (CEA, CA 15.3, CA 125 and CA 19.9) were negative too. On the other hand, neuroendocrine markers (NSE and CgA) were positive. A whole body scintigraphic scan plus thorax and abdomen single photon emission computed tomography (SPECT) with In-111 pentetreotide (222 MBq; 6 mCi) showed an uptake in the left mammary gland. No other pathological localisations were observed. The day after the intravenous injection of In-111 pentetreotide, the patient underwent RGS breast tumour resection and left axillary lymphadenectomy. In conclusion, we would like to emphasise: (1) the role of radionuclide imaging for the detection of breast NETs in relation to conventional diagnostic procedures; (2) the role of RGS in localising and removing a non-palpable breast NET that was undetectable with the use of conventional imaging techniques.

Small Cell Carcinoma of the Breast

Small cell carcinoma of the breast (SCCB) is an uncommon neoplasm that accounts for less than 1% of primary breast cancers. Histologically, these tumors have striking similarities to small call carcinoma of the lung, usually with evidence of associated ductal carcinoma-in-situ (DCIS) with areas of ductal, lobular, or papillary differentiation. Immunoreactivity for neuroendocrine markers is documented in two thirds of cases, while 33% to 50% are positive for estrogen receptor (ER) or progesterone receptor (PR). Her2/neu expression has not been reported in SCCB. Treatment, which may include surgery, radiotherapy, and combination chemotherapy, is based on clinical stage and the presence of metastases. Prognosis is variable and is dependent on the initial stage of disease.

[Breast carcinoma with predominant neuroendocrine differentiation]

Neuroendocrine differentiation can be identified in a subset of human breast carcinomas, either as scattered cells or as a predominant neuroendocrine component. We report a case of an invasive breast carcinoma largely composed of neuroendocrine cells. Eight years after a left mammary lumpectomy for a pT2N1MO SBR III invasive ductal carcinoma, a 67-years-old woman presented with a metastastic neuroendocrine sternal mass. To establish a relationship between mammary carcinoma and bone metastasis, histological slides of both the breast tumor and axillary lymph nodes were reviewed, and an immunohistochemical study was performed. They showed that: a) the mammary carcinoma was composed of a majority of small and large neuroendocrine cells synaptophysin +, NCAM+, chromogranin - (80%), associated with 2 other differentiated non endocrine components, one of metaplastic squamous carcinoma (10%) and the other of ductal carcinoma (10%); b) 4 axillary lymph nodes were involved by the ductal component which contained few NCAM + but synaptophysin - cells; c) Estrogen and progesterone receptors and HER2 were negative in the breast tumor and the metastatic nodes. We discuss the histogenesis of composite mammary carcinomas with neuroendocrine differentiation, the outcome of each component and the prognostic relevance of such a diagnosis.

Primary small cell neuroendocrine tumour of the breast

Primary neuroendocrine carcinomas of the breast are extremely rare. Tumours can only be considered small cell neuroendocrine tumour of the breast if nonmammary sites are excluded. These tumours form a diagnostic and therapeutic challenge. We present our experience of small cell neuroendocrine tumour of the breast and discuss a review of the relevant literature.

Composite type of breast carcinoma with endocrine differentiation: a cytological and immunohistochemical study

We describe a case of breast carcinoma with endocrine differentiation containing a mixture of three different histological features that occurred in a 71-year-old woman. Histologically, the tumor was predominantly intraductal, but slightly invasive. In the intraductal lesion, the tumor consisted mainly of ovoid to round cells with a modest to abundant amount of granular eosinophilic cytoplasm or intracytoplasmic mucin (mucin-producing carcinoma in situ). It also consisted, in part, of plump spindle cells with scant cytoplasm that contained argyrophilic granules in a trabecular pattern or an arrangement of perivascular pseudorosettes (atypical carcinoid tumor like-features). Mucous lake and tumor cells floating in mucin were seen in the invasive lesion (mucinous carcinoma). Immunohistochemical staining revealed endocrine differentiation of the tumor cells of both intraductal and invasive lesions. These findings suggest that the different histological features derived from pluripotent cells upon endocrine differentiation, and that endocrine differentiation of the tumor cells had already occurred at an earlier stage of carcinogenesis, prior to the appearance of the mucinous carcinoma. Cytologically, plasmacytoid tumor cells appeared in loosely cohesive clusters or as sparsely single cells in a background of a mucinous substance.

Tissue microarray analysis of neuroendocrine differentiation and its prognostic significance in breast cancer

The aim of this study was to detect neuroendocrine differentiation (NE), to determine its association with major clinicopathological parameters of breast cancer, and to study the prognostic significance of NE differentiation in a group of breast carcinomas by using tissue microarray (TMA) methodology. NE differentiation was studied by using 3 markers, synaptophysin (Syn), chromogranin A (ChA), and neuron-specific enolase (NSE) in a group of 334 patients with breast carcinoma. TMA blocks were made by using duplicate 0.6-mm-diameter tissue cores from each paraffin block. Results of immunostaining were scored on a 4-point scale, that is, as negative, weak, intermediate, and strong immunoreactivity. Positive staining of breast cancers for any of the 3 NE markers was detected in 19.5% of cases. Expression of a single marker was present in 16.2% of cases, and expression of 2 or 3 markers in combination was detected in 3.3% of cases. There was no statistically significant correlation of NE phenotype with tumor morphology, except mucinous carcinoma (3 of 6 cases positive), estrogen receptor, progesterone receptor, or nodal status. A weak correlation was noted between synaptophysin staining and higher tumor grade (P = 0.029). Analysis of disease-specific and overall survival based on up to 20 years of follow-up data showed a correlation between NSE expression and improved disease-specific (P = 0.043) and overall survival (P = 0.03) in univariate but not in multivariate analysis. The expression of Syn and ChA, as well as coexpression of multiple NE markers, had no prognostic significance.

Neuroendocrine differentiated carcinomas of the breast: a distinct entity

Some primary carcinomas of the breast have been classified as neuroendocrine. In this paper we report on 12 cases of neuroendocrine carcinoma of the breast displaying common and uncommon histological features.

MATERIALS AND METHODS

All patients were aged from 43 to 79 (median 66.5) years. The tumors were unilateral and ranged from 0.8 to 7 cm (median 2.35 cm) in diameter. Four tumors were classified as solid cohesive, two as solid papillary, one as Merkel cell-like, two as cellular mucinous, two as cellular mucinous with micropapillary features and one as cellular mucinous with prominent signet ring cells. The tissues were fixed in formalin and routinely processed. All materials were stained with PAS, Alcian blue and also hematoxylin and eosin. Immunohistochemical examination was carried out by the avidin-biotin method using the following antibodies: estrogen receptor protein, progesterone receptor protein, p53, cerbB-2, Ki67, neuron-specific enolase, chromogranin, and synaptophysin.

RESULTS

In all cases the tumor cells were stained positively with NSE. Synaptophysin and chromogranin positivity was detected in 11 and five cases, respectively. The prominent histological features were: extensive intraductal growth, pseudorosettes and palisades, low-grade cytologic atypia, plasmacytoid appearance of the tumor cells, and intracellular and extracellular mucin.

CONCLUSION

Neuroendocrine-differentiated carcinoma of the breast is a rare and distinct category with different histological subtypes.

34betaE12 cytokeratin immunodetection in the differential diagnosis of neuroendocrine carcinomas of the breast

Neuroendocrine (NE) carcinomas of the breast share morphologic and immunohistochemical features with NE tumors of other sites, either resembling typical carcinoids or the highly aggressive small cell carcinoma. In addition, some mucinous carcinomas or solid/papillary carcinomas may show a major NE component. This is generally recognized by specific immunodetection of pan-endocrine markers, although this approach may fail to recognize NE tumors lacking immunoreactivity for some NE products, because the antigen is produced but not retained in the cytoplasm. It has recently been reported that high molecular weight (HMW) cytokeratin (CK), recognized by clone 34betaE12, immunostaining selectively labels non-NE carcinomas (squamous-cell and adenocarcinomas) of the aerodigestive tract and lung. The role of such CK immunodetection in the differential diagnosis of NE carcinoma of the breast was evaluated. Twenty-four cases of breast carcinomas having NE differentiation were selected. Twenty-four cases of non-NE invasive breast carcinomas served as controls. HMW CK immunoreactivity was found in all but one case of non-NE carcinomas, but in only two NE tumors (having scattered positive cells only). The authors conclude that in breast carcinomas the presence of HMW CK immunoreactivity favors the diagnosis of non-NE carcinoma, whereas its absence supports that of a NE tumor (either a carcinoid or a small cell carcinoma or a mucinous carcinoma). HMW CK can be added to the list of markers useful in the differential diagnosis of NE from non-NE tumors.

Primary mammary small-cell carcinoma: a molecular analysis of 2 cases

Primary small-cell carcinoma of the breast is an exceedingly rare variant of breast carcinoma whose genetic profile has not been previously investigated. We report the molecular features of 2 cases of small-cell carcinoma of the breast: 1 with an adjacent intraductal carcinoma, and 1 with prior pleomorphic lobular carcinoma in situ. Laser capture microdissection followed by loss of heterozygosity (LOH) analysis revealed identical molecular alterations at multiple chromosomal regions, including BRCA-1, BRCA-2, p53, and retinoblastoma gene loci, in 1 case of small-cell carcinoma and its adjacent intraductal component. Additionally, LOH in 1 or both small-cell carcinomas was detected at 3p, 4q31.2-qter, 8p21-24, 11q13 (MEN-1 locus), 11q23.3, 11q24.1-25, 16q24.1 (H-cadherin locus), and 17q25. The results of our molecular analysis suggest that genetic changes in mammary small-cell carcinoma resembled those seen in both invasive ductal carcinomas and pulmonary small-cell carcinoma. Second, mammary small-cell carcinoma is clonally related to ductal carcinoma in situ and might represent an example of divergent differentiation occurring in a multipotential neoplastic stem cell.

Primary small cell (oat cell) carcinoma of the breast: report of a case and review of the literature

A case of primary small cell (oat cell) carcinoma of the breast in a 41-year-old woman is presented. The patient was alive and well without disease 16 months after modified radical mastectomy and subsequent chemotherapy. The tumor cells revealed morphologic similarity to oat cell carcinoma of the lung and immunohistochemical expression of neuroendocrine markers. In ultrastructural examination, the tumor cells had neurosecretory granules. Review of nine previously reported cases and this case of primary small cell carcinoma of the breast has revealed that this type of tumor shows prominent vascular invasion, frequent lymph node metastasis, infrequent expression of estrogen receptor, and also very poor prognosis. Immunohistochemical study for the c-kit proto-oncogene product, which has been reported to be a specific marker for pulmonary small cell carcinoma, demonstrated positive reactivity in approximately 80% of the tumor cells of this case, which is the first report according to our knowledge. The expression of c-kit might be some aid to the diagnosis of primary small cell carcinoma of the breast.

Small cell carcinoma of the breast: a clinicopathologic and immunohistochemical study of nine patients

Small cell carcinoma of the breast is an uncommon neoplasm that has been reported rarely in the literature. The aim of this study was to characterize better the pathologic and immunohistochemical features of this neoplasm. Nine examples of mammary small cell carcinoma were retrieved from the authors' consultation files and reviewed. The patients ranged in age from 43 to 70 years. Two patients had a previous history of cutaneous malignant melanoma and one had prior lobular carcinoma in situ and atypical duct hyperplasia in the same breast as the small cell carcinoma. Eight patients presented with a mass in the breast; one patient had an axillary tumor. Tumor size ranged from 1.3 to 5.0 cm (mean, 2.6 cm). Histologically, the nine tumors had characteristics of small cell carcinoma with high mitotic activity and necrosis. A dimorphic histologic appearance was observed in four tumors. In one instance, this consisted of small cell carcinoma merging with invasive lobular carcinoma. In three cases, small cell carcinoma was present together with invasive, poorly differentiated duct carcinoma; invasive carcinoma with "lobular and gland-forming elements"; and focal squamous differentiation, respectively. Lymphatic tumor emboli were identified in four instances. An in situ component was seen in seven tumors; five were of the small cell type in ducts and two were of the ductal type with high nuclear grade. Immunohistochemical analysis showed consistent staining for cytokeratin markers but variable staining with neuroendocrine markers. Sixty-six percent of the tumors (six of nine) were reactive for chromogranin, synaptophysin, or peptide hormones, including four positive for chromogranin and synaptophysin, one positive for synaptophysin and calcitonin, and one positive for calcitonin alone. One tumor that was reactive for chromogranin and synaptophysin also contained calcitonin immunoreactive cells, whereas gastrin-releasing peptide was present in two other tumors that were also positive for chromogranin. Leu 7 was positive in three cases that were reactive for either chromogranin or synaptophysin. Five tumors were estrogen and progesterone receptor-positive. All tumors were positive for bcl-2 and negative for HER2/neu. Patients were treated by mastectomy (n = 3) or lumpectomy (n = 6). Eight underwent an axillary dissection that revealed metastatic carcinoma in four patients. Seven patients received adjuvant chemotherapy and four patients received radiation. Two patients also received tamoxifen treatment. Metastases developed in two patients (22%) with a follow-up period of 11 and 32 months. All patients were alive at last follow up 3 to 35 months after treatment. When compared with published reports of mammary small cell carcinoma, our results show that the prognosis in these patients may not be as poor as previously suggested.