Mucinous cystadenocarcinoma of the breast

Primary Mucinous Cystadenocarcinoma of the Breast: Clinicopathological Analysis of a Case and Difficulties Encountered in a Biopsy

Background. With <40 case reports published in the English literature, mucinous cystadenocarcinoma of the breast is quite rare compared to its counterparts in the ovary, pancreas, and appendix. The purpose of this case report is to enrich scientific data by sharing the clinicopathological features of this new and extremely rare entity and present possible difficulties encountered in the biopsy materials. Case Report. A 34-year-old female patient presented with the complaint of white discharge from her left nipple lasting 8 months. Physical and radiological examination of the patient revealed a mass in the lower quadrant of the left breast and tru-cut biopsy was performed. The diagnosis of invasive breast carcinoma of no special type was reported. After neoadjuvant chemotherapy, left subcutaneous mastectomy and left sentinel lymph node biopsy were performed. Microscopic evaluation of the mastectomy material revealed a tumor consisting of stratified columnar cells with basally located nuclei and intracytoplasmic mucin, showing papillary structures and tufting toward the lumen. Peripheral myoepithelial cells were not identified with p63 and calponin immunohistochemistry. The diagnosis of mucinous cystadenocarcinoma was given through histomorphological and immunohistochemical evaluations. Conclusion. Clarifying unknown points about this rare malignancy of the breast and understanding the tumor biology is possible through evaluation of case reports. For this purpose, our case of primary mucinous cystadenocarcinoma is presented and its clinicopathological features are briefly discussed.

HER2-positive mucinous cystadenocarcinoma of the breast coexisting with invasive lobular carcinoma: A case report and review of the literature

Primary mucinous cystadenocarcinoma (MCA) of the breast is a rare variant of breast carcinoma. A 68-year-old female patient presented to the general surgery clinic with pain and swelling in the right breast. A mass was detected in the upper outer quadrant, and a fine-needle aspiration biopsy was performed. The May-Grünwald Giemsa stained slides showed aggregates of mucin-rich pleomorphic cells with large nuclei in a mucinous background containing discohesive single cells. The Papanicolaou stain revealed a papillary structure composed of malignant epithelial cells in a necrotic background. A modified radical mastectomy was performed, and upon gross examination, two tumors were discovered in the central and upper outer quadrants. The first tumor, located centrally, was identified as invasive lobular breast carcinoma. The second tumor was an MCA with cytokeratin 7(+) and cytokeratin 20(-), and was determined to be the primary MCA of the breast based on clinical and radiological information. Immunohistochemistry revealed that the tumor cells were negative for estrogen receptor and progesterone receptor, and HER2 was 2+. Fluorescence in situ hybridization analysis detected HER2 gene amplification. During the 72-month follow-up, there were no findings compatible with recurrence or new metastasis. Although primary MCA is rare, it causes differential diagnosis problems and has different biological behaviors.

Invasive papillary carcinoma of the breast

Invasive papillary carcinoma is a rare form of breast cancer that is more likely to occur in postmenopausal women. Previous studies have been limited to case reports and small retrospective studies, leading to low awareness of this type of tumor and difficult clinical management. According to the available literature, invasive papillary carcinoma exhibits unique pathological features and biological behaviors. Invasive papillary carcinoma is mostly luminal type, with a low rate of lymph node metastasis, which underlies its favorable prognosis. The effectiveness of adjuvant therapy in reducing tumor burden and improving prognosis in patients with invasive papillary carcinoma remains uncertain. Due to the rarity of the lesion, conducting prospective clinical trials is impractical. The use of biological models, such as organoids, can help alleviate the impact of the scarcity of this condition on research. In addition, invasive papillary carcinoma is affected by specific genomic events, and more extensive studies of gene expression profiling may provide molecular-level insights to make optimal therapeutic decisions.

Mucinous cystadenocarcinoma of the breast harbours TRPS1 expressions and PIK3CA alterations

AIMS

Breast mucinous cystadenocarcinoma (BMCA) is a rare tumour recently recognised as a distinct entity by the World Health Organisation Tumour Classification Series. BMCA is a triple-negative tumour that lacks specific immunohistochemical markers; therefore, distinguishing it from mimickers such as ovarian and pancreatic cystadenocarcinomas requires careful clinicopathological correlation. Due to its rarity, little is known about the molecular alterations that underlie BMCA.

METHODS AND RESULTS

In this study, we used immunohistochemical staining methods to investigate TRPS1 (trichorhinophalangeal syndrome type 1) expression in BMCA and compare it to expression in ovarian and pancreatic mucinous cystadenocarcinomas. We also collected tumour samples from three BMCA patients for molecular analysis by MALDI-TOF mass spectrometry, real-time polymerase chain reaction, whole exome sequencing and fluorescence in-situ hybridisation. TRPS1 immunoreactivity was found only in BMCA tumour cells and not in the ovarian and pancreatic counterparts. One of the three BMCA tumours also showed a PIK3CA hot-spot mutation, which was confirmed by whole genome next-generation sequencing (NGS). No KRAS, NRAS, BRAF or AKT mutations were found.

CONCLUSIONS

To our knowledge, this is the first demonstration of TRPS1 expression in BMCA patients and the first identification of a PIK3CA hotspot mutation in these tumours. These findings provide insights into the molecular mechanisms underlying BMCA tumorigenesis and suggest a potential drug target for this rare and poorly understood cancer.

Primary Mucinous Cystadenocarcinoma of the Breast Intermixed with Pleomorphic Invasive Lobular Carcinoma: The First Report of This Rare Association

Primary mucinous cystadenocarcinoma (MCA) is a rare breast carcinoma subtype showing overlapping histopathological features with mucinous cystadenocarcinoma of the ovary and pancreas. Current literature data suggest a favorable prognosis of breast MCAs despite its immunoprofile usually revealing lack of expression of estrogen receptor, progesterone receptor and HER-2 and high Ki67. As far as we know, only 36 cases have been reported in the literature to date. Its ambiguous morpho-phenotypic profile makes histological diagnosis very challenging. It must be distinguished from typical mucin-producing breast carcinomas and, above all, metastases from the same histotype in other sites (ovary, pancreas, appendix). Herein, we report the case of a primary breast MCA occurring in a 41-year-old female with peculiar histological features.

Mammary mucinous cystadenocarcinoma with long-term follow-up: molecular information and literature review

BACKGROUND

Mucinous cystadenocarcinoma (MCA) is a very rare form of breast cancer that was first described in 1998. Only 33 cases of primary MCA, including our present case, have been reported thus far. As a consequence, its molecular features, prognosis and treatment regimen are poorly known. Here, we describe a less common presentation of MCA, detail its molecular features, discuss the major differential diagnosis, and provide a brief review of the literature.

CASE PRESENTATION

A 59-year-old woman presented with a breast lump in which mammography showed a well-defined nodule. Core needle biopsy (CNB) revealed several lesions lined by tall columnar cells with stratification and abundant mucinous secretion; excision was recommended for final diagnosis. The resected specimens showed cavities of different sizes without surrounding myoepithelial cells. The cavities were rich in mucus, and the nuclei were located at the base of the cells, containing intracellular mucus. Immunohistochemical analysis revealed that it was triple-negative breast cancer (TNBC). Next-generation sequencing (NGS) revealed pathogenic mutations in the PIK3CA, KRAS, MAP2K4, RB1, KDR, PKHD1, TERT, and TP53 genes. A diagnosis of MCA was rendered. The patient has been followed up for 108 months to date and showed no signs of recurrence or metastasis.

CONCLUSION

Our study presents the gene profile of an MCA case with no recurrence or metastatic tendency after 108 months of follow-up, and a review of the literature helps us better understand the clinical, pathologic, and molecular features of this tumor.

The Spectrum of Mucinous Lesions of the Breast

CONTEXT.—

Mucinous lesions of the breast encompass many entities ranging from benign to malignant and nonneoplastic to neoplastic. Lesions discussed under this category are mucocele-like lesion, mucinous carcinoma, mucinous micropapillary carcinoma, solid papillary carcinoma, mucinous cystadenocarcinoma, mucoepidermoid carcinoma, invasive lobular carcinoma with extracellular mucin, mucinous ductal carcinoma in situ, and metastasis.

OBJECTIVE.—

To review clinical, pathologic, and molecular features of mucinous lesions of the breast, their differential diagnoses, and challenging features on core needle biopsies.

DATA SOURCES.—

The existing scientific and clinical literature as of December 2021.

CONCLUSIONS.—

The category of mucinous lesions of the breast is vast and the differential diagnosis can be challenging, especially on core needle biopsies. In all cases, clinical, radiologic, and pathologic correlation is necessary to reach a comprehensive diagnosis. Given that the prognosis and management of each entity is different, being aware of these entities and their nuances is critical for a pathologist to guide accurate management.

Mucinous carcinoma of the breast: distinctive histopathologic and genetic characteristics

Mucinous carcinoma is a rare histologic type of breast cancer that, when classified with favorable histology, can be treated with different therapeutic options. This study reviews the histologic findings of mucinous carcinoma that support or exclude favorable histology and emphasizes the necessity of an appropriate gross examination with radiologic findings for an accurate diagnosis. In addition, unusual findings such as micropapillary arrangements and lobular differentiation in mucinous carcinoma and their implications for prognosis and treatment are reviewed. Mucinous carcinoma involves upregulation of MUC2, a mucus-associated gene common in mucinous carcinoma of the breast as well as various other organs. In mucinous carcinoma, the fraction of genome altered and tumor mutation burden are lower than those of invasive carcinoma of no special type, the most common histology of breast cancer. In addition, the genetic alterations found in mucinous carcinoma are diverse, unlike the pathognomonic genetic alterations observed in other histologic types of breast cancer. These genetic features support the importance of conventional microscopic evaluations for the pathologic differential diagnosis of mucinous carcinoma of the breast in routine practice. A variety of breast lesions, including mucinous cystadenocarcinoma and mucocele-like lesions, as well as mucinous carcinoma from other organs, can mimic mucinous carcinoma of the breast. In order to obtain an accurate pathologic diagnosis, careful evaluation of the overall histopathologic characteristics and ancillary testing are required to provide information on appropriate treatment and prognosis.

Primary Breast Mucinous Cystadenocarcinoma and Review of Literature

Mucinous cystadenocarcinoma of the breast is a rare primary breast carcinoma having distinct clinical behavior and a favorable prognosis. It has a characteristic morphology that must be differentiated from metastatic ovarian and pancreatic mucinous adenocarcinoma. The etio-pathogenesis, genetic profile, and treatment of this tumor are controversial. Here, we report a case of primary mucinous cystadenocarcinoma of the breast in a 61-year-old female. The case is of interest since it is uncommon and has peculiar clinical and morphological features.

Special Histologic Type and Rare Breast Tumors - Diagnostic Review and Clinico-Pathological Implications

Breast cancer is the most common malignant tumor in females. While most carcinomas are categorized as invasive carcinoma, no special type (NST), a diverse group of tumors with distinct pathologic and clinical features is also recognized, ranging in incidence from relatively more common to rare. So-called "special histologic type" tumors display more than 90% of a specific, distinctive histologic pattern, while a spectrum of tumors more often encountered in the salivary gland may also arise in the breast. Metaplastic carcinomas can present diagnostic challenges. Some uncommon tumors harbor pathognomonic genetic alterations. This article provides an overview of the key diagnostic points and differential diagnoses for this group of disparate lesions, as well as the salient clinical characteristics of each entity.

Mucinous cystadenocarcinoma of the breast: a new entity with broad differentials-a case report

BACKGROUND

Mucinous cystadenocarcinoma is a rare and recently described primary breast cancer with strikingly similar histomorphology to ovarian, pancreatic, and gastrointestinal counterparts. The diagnosis cannot be made until the metastatic lesion is ruled out.

CASE PRESENTATION

We are reporting the case of a 65-year-old woman with primary mucinous cystadenocarcinoma of the breast while exploring clinicopathological features and approach to diagnosis. Though the immunohistochemistry panel of CK7, CK20, CDX2, SATB2, PAX8, mammoglobin, and GATA3 plays a crucial role in ruling out metastasis but aberrant CK20 positivity was seen in our case, the final diagnosis was made after a complete radiological workup. We also noted strong membranous HER2-protein expression and HER2-gene amplification by fluorescence in situ hybridization while in literature this tumor is reported to show mainly triple-negative basal type immunophenotype.

CONCLUSION

A combined clinic-radio-immunohistochemical approach is essential to make a diagnosis of primary mucinous cystadenocarcinoma.

Papillary lesions of the breast

Papillary lesions of the breast represent a heterogeneous group of lesions including benign papillomas, papillomas with focal epithelial atypia, fully fledged ductal carcinoma in situ (DCIS) or lobular neoplasia, papillary DCIS, encapsulated papillary carcinomas without or with invasion, solid papillary carcinomas, and invasive papillary carcinomas. A micropapillary pattern characterized by lack of fibrous stalks within the papillae is observed in micropapillary DCIS and invasive micropapillary carcinoma. In addition, a variety of other rare breast lesions reveals a papillary architecture such as tall cell carcinoma with reversed polarity (TCCRP) and mucinous cystadenocarcinoma, adenomyoepithelioma, and secretory carcinoma. In addition, benign lesions such as usual ductal hyperplasia, apocrine metaplasia, gynecomastia, and juvenile papillomatosis may show a papillary or micropapillary architecture. Fragments of a benign papilloma in a breast biopsy are considered a lesion of uncertain malignant potential (B3 in the European classification) and excision is mostly recommended. Although the knowledge about molecular pathology of papillary breast lesions has increased, there is not sufficient evidence for diagnostically useful molecular features, yet. The aim of this review is to provide an update on papillary and micropapillary lesions with emphasis on problematic areas for daily diagnostic work including biopsies.

Mucinous cystadenocarcinoma of breast in a 69-year-old woman with positive hormone receptors, the first case reported

Background:

Mucinous cystadenocarcinoma is a relatively uncommon histological subtype of breast cancer that is a cystic form of papillary mucinous carcinoma.  It is regularly negative for estrogen and progesterone receptors and it is most often diagnosed in older than 55-60 years old. The incidence of breast mucinous cystadenocarcinoma is about 1-6% of primary breast cancers. Here, we present a case of breast mucinous cystadenocarcinoma of left breast in a 69-year-old female which is positive for estrogen and progesterone receptors.

Case Presentation:

In this article, we describe a case of a-69-year-old female with a painful mass in her left breast. Based on intraoperative pathology consult, neoplastic tissue mostly floating in mucinous lakes with invasion to surrounding stroma was seen. Immunohistochemistry profile showed positive estrogen and progesterone receptors and negative for HER2.

Conclusion:

Mucinous cystadenocarcinoma of breast is typically triple negative for hormone receptors. But ER and PR positive variant of this tumor is rare, giving the chance of a better prognosis for the patient with hormonal therapy.

Genetic profile of primary mucinous cystadenocarcinoma of the breast-A case report

Primary mucinous cystadenocarcinoma of the breast is a rare neoplasm with few reports in the literature. Here, we report for the first time a comprehensive genetic profile of a primary mucinous cystadenocarcinoma of the breast, using next-generation sequencing 580 cancer-associated gene panel. Mutations in TP53, RB1, and BAP1 were identified. The findings suggest that this tumor is driven mostly by abnormalities in tumor suppressor genes, primarily involved in cell cycle control and chromatin remodeling. Molecular characterization of additional primary mucinous cystadenocarcinomas of the breast is warranted and might provide information related to its biology and behavior.

Rare Breast Cancer Subtypes

PURPOSE OF REVIEW

Breast cancer is a collection of diseases including the more common invasive ductal and lobular carcinomas and rarer subtypes of breast cancer. This review summarizes the features of rare breast cancers.

RECENT FINDINGS

Each of the rare tumors has defined pathological and clinical features that impact treatment recommendations. In this review, we summarize these for each rare type of breast cancer and where available we include molecular features of each tumor. Rare subtypes of breast cancer each have unique features. In many cases, data is limited for the optimal treatment approaches.

Primary Mucinous Cystadenocarcinoma of the Breast: A Rare Case Report With Review of Literature

Primary mucinous cystadenocarcinoma (MCA) of the breast is a rare variant of breast carcinoma known to have a favorable prognosis despite showing a basal-like phenotype. We describe a case of MCA breast in a 45-year-old female with a palpable mass in the breast. On the basis of the histopathological and immunohistochemical evaluation of a lumpectomy specimen with the absence of mass anywhere else on whole-body imaging, a diagnosis of primary MCA was rendered. Mismatch repair protein evaluation showed this tumor to be microsatellite stable. Molecular testing revealed the absence of Kirsten rat sarcoma viral oncogene homolog (KRAS), neuroblastoma RAS viral oncogene homolog (NRAS), and v-raf murine sarcoma viral oncogene homolog B1 (BRAF) mutations. To date only 27 cases of MCA breast have been reported. To the best of our knowledge, ours is the first case documenting diffuse Cytokeratin 20 (CK20) positivity, microsatellite stability, and the absence of KRAS, NRAS, and BRAF mutations in these tumors. The rarity of this tumor further evokes an interest in this case. A better understanding of the disease warrants a review of more cases with longer follow-ups.

Invasive breast cancer: Current perspectives and emerging views

Invasive breast cancer constitutes a heterogeneous group of tumors. They comprise various histological types that differ in clinical presentation, imaging features, histopathological characteristics, biomarker profiles, prognostic and predictive parameters. The current classification of invasive breast cancer is based primarily on histopathological features. Invasive carcinoma of no special type accounts for the majority, with some rare entities also being described. With recent research and advances, there are emerging concepts, including new genetic insights of invasive breast cancer and the role of the stromal microenvironment. With greater understanding of the pathogenesis of invasive breast cancer, changes based on the correlation of histologic and genetic findings have been incorporated in the latest World Health Organization classification of breast tumors. Medullary carcinomas are subsumed as invasive carcinoma of no special type with basal-like and medullary features, regarded as part of the spectrum of tumor infiltrating lymphocyte-rich breast cancers. Tall cell carcinoma with reversed polarity is proposed as a distinct entity in recognition of unique IDH2 mutations. This article reviews conventional prognostic parameters, new histological entities, and updates on breast cancer classification, with inclusion of some genetic insights into breast cancer and the role of tumor infiltrating lymphocytes.

Fine-needle aspiration cytology of solid papillary carcinoma of the breast

We report a case of solid papillary carcinoma (SPC) of the breast, of which the cytologic findings of the nipple discharge and the fine needle aspiration (FNA), and the pathology of the resected tumour are described in detail. Imaging studies demonstrated an intra-ductal tumour of the breast, which seemed responsible for the bloody nipple discharge. The cytologic features of the nipple discharge and the FNA targeted to the intra-ductal tumour suggested low-grade carcinoma. Additional findings of mucin production and rosette-formation (possibly neuroendocrine differentiation) indicated SPC as a major differential diagnosis. Histologically, the lesion consisted of mainly ductal proliferation of low-grade carcinoma associated with prominent rosette formation within the tumour and mucin production. Permeation of mucin with cancer cell clusters into the adjacent adipose tissue was also noted. Immunohistochemically, the tumour cells, especially those forming rosettes, were partially positive for CD56. Histological diagnosis was SPC with invasion. SPC is a rare tumour, and its cytologic and pathologic features have only been sporadically reported. Our case was unique in that there was a good correlation between cytologic and histologic findings. The cytologic findings that are important to predict the histologic diagnosis are emphasized. A brief review of the relevant literature is also included.

Mucinous Cystadenocarcinoma of the Breast: Report of 2 Cases Including One With Long-Term Local Recurrence

Primary mucinous cystadenocarcinoma (MCA) of breast is an exceedingly rare tumor with histologic resemblance to MCA arising in ovary, pancreas, and gastrointestinal tract. In this article, we present 2 additional cases of MCA of breast, one highlighting the diagnostic challenges of a rare entity that may potentially lead to unnecessary chemotherapy and the second case presenting with recurrence after 8 years of primary surgical excision defying the indolent behavior reported in the literature. To our knowledge, this is the first reported instance of such behavior.

Mucinous breast carcinoma with tall columnar cells

Mucinous carcinoma of the breast represents 1%-4% of all breast cancers. The World Health Organization classification divides this type of tumour into three different subtypes: mucinous carcinoma, mucinous carcinoma with tall columnar cells (mucinous cystadenocarcinoma and columnar cell mucinous carcinoma) and signet ring cell carcinoma. A 74-year-old woman presented a tumour with inflammatory features in the upper outer quadrant of her left breast, 7 cm in diameter. The core biopsy showed infiltrating ductal carcinoma of no specific type. The tumour-node-metastasis clinical staging was T4cN3M0 (Stage IIIC). She received neoadjuvant chemotherapy, underwent left mastectomy with radical axillary resection and subsequently received radiotherapy and chemotherapy. The histological examination of the surgical specimen revealed two solid tumors in the tail of Spence, which corresponded to adenocarcinoma with high columnar cells. The patient died 16 months after the diagnosis, suffering from pulmonary metastases and anterior chest wall infiltration. A review of the literature revealed only 21 reports of mucinous carcinoma of the breast with tall columnar cells, including our case. This is only the third time that the specific histological type of columnar cell mucinous carcinoma has been reported in the literature.

Mucinous cystadenocarcinoma of the breast: the challenge of diagnosing a rare entity

Mucinous cystadenocarcinoma is an extremely rare variant of primary breast tumor which is histologically similar to mucinous cystadenocarcinoma of the ovary and pancreas. Herein we report a case of a 63 years old woman diagnosed with diverse histological types of non-synchronous rare primary breast tumors, a medullary carcinoma of the right breast and a mucinous cystadenocarcinoma of the left breast. Macroscopically the neoplasm appeared multilocular filled with mucoid material. Under light microscopy the cystic areas were lined by columnar cells with abundant intracellular and extracellular mucin. Solid areas were composed of tall columnar cells with intracellular mucin. Moderate to marked atypia was noticed and tumor cells stained positive for cytokeratin 7 and negative for cytokeratin 20. Moreover tumor cells displayed a basal like immunophenotype expressed as followed: ER negative, PR negative, HER-2 negative, cytokeratin (CK5/6) positive and EGFR positive.

Mammary Mucinous Carcinoma in the Cat

Mucinous carcinoma of the mammary gland is a rare tumor characterized by excessive mucin production. In human and canine pathology, the diagnosis of mucinous carcinoma is based on the demonstration of an epithelial phenotype of mucus-producing cells and periodic acid-Schiff (PAS)-diastase positivity of the mucin. The histologic and immunohistologic characteristics of feline mucinous mammary carcinoma were examined. Of 656 cases of feline mammary neoplasms and dysplasias, 3.2% were found to be mucin-producing tumors. Cytokeratin 19 (16 cases positive, 4 heterogenous, and 1 negative) and vimentin (15 cases positive, 2 heterogenous, and 4 negative) expression were examined, and the mucin produced was alcian blue positive. PAS-diastase staining was variable (38.1%). Based on these findings, mucinous mammary carcinoma in the cat varies significantly from the human and canine varieties and alcian blue is the prominent stain in the diagnosis of feline mucinous carcinoma.

Primary mucinous cystadenocarcinoma of the breast with endocervical-like mucinous epithelium

BACKGROUND

Primary mucinous cystadenocarcinoma of the breast is an extremely rare entity. To the best of our knowledge, only 17 patients have been described in the PubMed database.

CASE REPORT

Here, we report a primary breast mucinous cystadenocarcinoma with endocervical-like mucinous epithelium in a 62-year-old woman. The patient was followed for 5 months without any adjuvant treatment and she continues to be disease free.

CONCLUSIONS

Primary breast mucinous cystadenocarcinoma usually displays unique pathologic and immunohistochemical characteristics simulating its ovarian counterparts; it seems to have a good prognosis after complete resection.

Primary Mucinous Cystadenocarcinoma of the Breast: Cytologic Finding and Expression of MUC5 Are Different from Mucinous Carcinoma

Mucinous cystadenocarcinoma (MCA) in the breast is a rare neoplasm. There have been 13 cases of primary breast MCA reported. The MCA presents as a large, partially cystic mass in postmenopausal woman with a good prognosis. The microscopic findings resemble those of ovarian, pancreatic, or appendiceal MCA. The aspiration findings showed mucin-containing cell clusters in the background of mucin and necrotic material. The cell clusters had intracytoplasmic mucin displacing atypical nuclei to the periphery. Histologically, the tumor revealed an abundant mucin pool with small floating clusters of mucin-containing tumor cells. There were also small cysts lined by a single layer of tall columnar mucinous cells, resembling those of the uterine endocervix. The cancer cells were positive for mucin (MUC) 5 and negative for MUC2 and MUC6. This mucin profile is different from ordinary mucinous carcinoma and may be a unique characteristic of breast MCA.

Mucinous cystadenocarcinoma of the breast with amplification of the HER2-gene confirmed by FISH: The first case reported

We present the first case of a primary mucinous cystadenocarcinoma of the breast that, in addition to the characteristic immunophenotype (CK7(+), CK20(-), ER(-), PR(-), and cdx2(-)), showed a strong membranous HER2-protein expression and HER2-gene amplification documented by fluorescence in situ hybridization.

Mucinous Cystadenocarcinoma of the Breast with Estrogen Receptor Expression: A Case Report and Review of the Literature

Primary mucinous cystadenocarcinoma (MCA) of the breast was first described by Koenig and Tavassoli in 1998. To our knowledge, only 9 cases of MCA of the breast have been reported. The optimal treatment of MCA could not be defined yet. This article aims to increase the knowledge about this rare variant of breast cancer and to review the literature.

Mucinous Lesions of the Breast

Breast lesions associated with extracellular mucin production are uncommon and constitute a wide spectrum of lesions ranging from benign cyst to mucinous carcinoma. Intracytoplasmic mucin can be seen rarely in benign metaplasias but is a common finding in invasive and in situ carcinomas. In this article, we discuss the differential diagnosis of breast lesions associated with mucin production and other entities that show histologic changes that mimic mucin production.

Mucinous cystic neoplasms of the mesentery: a case report and review of the literature

Background

Mucinous cystic neoplasms arise in the ovary and various extra-ovarian sites. While their pathogenesis remains conjectural, their similarities suggest a common pathway of development. There have been rare reports involving the mesentery as a primary tumour site.

Case presentation

A cystic mass of uncertain origin was demonstrated radiologically in a 22 year old female with chronic abdominal pain. At laparotomy, the mass was fixed within the colonic mesentery. Histology demonstrated a benign mucinous cystadenoma.

Methods and results

We review the literature on mucinous cystic neoplasms of the mesentery and report on the pathogenesis, biologic behavior, diagnosis and treatment of similar extra-ovarian tumors. We propose an updated classification of mesenteric cysts and cystic tumors.

Conclusion

Mucinous cystic neoplasms of the mesentery present almost exclusively in women and must be considered in the differential diagnosis of mesenteric tumors. Only full histological examination of a mucinous cystic neoplasm can exclude a borderline or malignant component. An updated classification of mesenteric cysts and cystic tumors is proposed.

A retrospective review with long term follow up of 11,400 cases of pure mucinous breast carcinoma

BACKGROUND

Pure mucinous breast carcinoma (PMBC) is a rare histologic type of mammary neoplasm. It has been associated with a better short-term prognosis than infiltrating ductal carcinoma (IDC) but identical long-term survival curves have been reported. The value of tumor size for TNM staging has been challenged because of the mucin content of the lesions. This study presents a large PMBC series with 20 years follow up as compared to IDC. The relative significance of a variety of common prognostic factors is calculated for this uncommon histology.

MATERIALS AND METHODS

A retrospective analysis of all PMBC cases reported in the SEER database between 1973 and 2002 was conducted. Overall survival (OS) and disease specific survival (DSS) were calculated at 5, 10, 15 and 20 years of follow up. Those curves were compared with all the IDC cases reported into the database during the same period. The prognostic significance of gender, race, laterality, age at diagnosis, T and N status, estrogen and progesterone receptors and administration of radiation therapy was calculated by univariate and multivariate analysis.

RESULTS

There were 11,422 PMBC patients reported. The median age at diagnosis was 71 years (Range 25-85). Fifty three percent of the tumors were well differentiated, 38% were moderately differentiated and the remaining 9% were poorly differentiated or anaplastic. The majority of the tumors were located in the upper outer quadrant (44%) the other 56% were roughly evenly divided between the upper inner, lower inner, lower outer and central quadrants. Eighty six percent of the patients had only localized disease at the time of surgery without nodal or distant disease while 12% had regional nodal involvement and 2% had distant metastases. The PMBC cases showed a better differentiation with lesions of lesser grade and more frequent ER/PR expression, smaller size and lesser nodal involvement when compared to the IDC cases of the same period. Kaplan Meier survival curves revealed a 5 years. breast cancer specific survival rate of 94%. Although slowly decreasing with time, 10, 15 and 20 years survival were 89%, 85% and 81% respectively compared to 82% (5 year), 72% (10 year), 66% (15 year) and 62% (20 year) for IDC. There were no significant differences in overall survival. Multivariate analysis by Cox regression revealed the nodal status (N) to be the most significant prognostic factor followed by age, tumor size (T), progesterone receptors and nuclear grade. Disease specific survival curves stratified for nodal status revealed a highly significant difference between node negative and node positive patients. The addition of radiation therapy after surgery did not significantly improve overall survival.

CONCLUSIONS

This large retrospective comparative analysis confirms the less aggressive behavior of PMBC compared to IDC. This favorable outcome is maintained after 20 years. This tumor presents typically in older patients and is rarely associated with nodal disease. Positive nodal status appears to be the most significant predictor of worse prognosis.

Prognostic Significance of Micropapillary Pattern in Pure Mucinous Carcinoma of the Breast

Breast carcinoma with micropapillary architecture is associated with aggressive behavior. Similar micropapillary pattern in pure mucinous carcinoma has been noticed and has been shown to convey poor prognosis. In this study 17 cases of pure mucinous carcinoma of the breast seen during a 10-year period have been reviewed, with special reference to micropapillary pattern. Diffuse micropapillary pattern was seen in 6 of 17 cases of mucinous carcinoma of the breast and demonstrated reverse polarity immunostaining pattern with “Epithelial Membrane Antigen.” In all cases, the tumor cells showed grade I morphology, and no lymph node metastases were noticed. All the tumors except 1 expressed strong estrogen and progesterone receptor expression, however, all the cases were negative for Her-2/neu expression. In this present study, mucinous carcinomas with micropapillary pattern showed a low nuclear grade, higher incidence of hormone receptor positivity, and lower incidence of Her-2/neu similar to mucinous carcinomas without micropapillary pattern, thus explaining their indolent behavior.

Cystic hypersecretory carcinoma: rare and poorly recognized variant of intraductal carcinoma of the breast. Report of five cases

AIMS

To report five cases of a rare variant of intraductal carcinoma of the breast, so-called cystic hypersecretory carcinoma. The clinical and pathological characteristics of the lesion are described, along with a review of the literature.

METHODS AND RESULTS

The patients were females aged between 53 and 78 years (average 66.8 years). The size of the lesions ranged between 70 and 80 mm in largest dimension. In two cases, the development of high-grade invasive ductal carcinoma was observed; in one additional case there was recurrence of high-grade in-situ carcinoma after 3 years. This emphasizes the importance of correct diagnosis of this potentially aggressive lesion. Strong over-expression of HER-2/neu protein was observed in three cases, including the two with an invasive component. Protein p53 was variably positive in all cases. Steroid receptor immunohistochemistry yielded variable results with only one case being positive for both oestrogen and progesterone receptors. Interestingly, in most cases (4/5) staining for androgen receptors was observed.

CONCLUSIONS

Cystic hypersecretory ductal carcinoma of the breast is a rare distinctive variant of ductal carcinoma in situ. It has the potential for invasive growth and the development of metastases.

Mucinous cystadenocarcinoma of the breast coexisting with infiltrating ductal carcinoma

A recently described and rare variant of breast carcinoma, mucinous cystadenocarcinoma (MCA), is reported in a 65-year-old post-menopausal woman. She presented with a gradually enlarged breast tumor. A well-circumscribed tumor measuring about 3 cm in diameter was noted in the mammographic and ultrasonographic examinations. The mammographic and ultrasonographic findings were indistinguishable from more common mucinous carcinoma (colloid carcinoma) of the breast. The gross appearance of the tumor was well-defined and cystic, consisting of abundant transparent to bloody mucin, as well as whitish solid parts. Microscopically, the tumor was characterized by abundant extracellular and intracellular mucin. It looked like a mucinous cystic neoplasm of the ovary and pancreas. Particularly, few microscopic foci of ordinary intermediate-grade infiltrating ductal carcinoma (IDC) and ductal carcinoma in situ (DCIS) were observed around the main lesion in this case. A transition from ordinary DCIS to MCA in situ was found. It might indicate MCA derives from a metaplasia process of ordinary DCIS. MCA can be easily differentiated from mucinous carcinoma by quite different histologic and immunohistochemical findings. According to the previously reported and present cases, MCA of the breast more commonly affects elderly women and has a relatively favorable prognosis.

Current Practical Applications of Diagnostic Immunohistochemistry in Breast Pathology

In recent years, immunohistochemistry has assumed an increasingly prominent role in diagnostic breast pathology. Immunohistochemistry is now frequently used in the evaluation of many epithelial proliferations of the breast. Common applications include the use of myoepithelial markers to evaluate for stromal invasion, E-cadherin to distinguish between ductal and lobular neoplasia, high molecular weight cytokeratins to differentiate usual ductal hyperplasia from ductal carcinoma in situ, immunohistochemical profiles to characterize site of origin of metastatic carcinomas, and cytokeratin stains to detect metastases in sentinel lymph nodes. Recent advances, practical considerations, and potential pitfalls in the use of immunohistochemistry in these five diagnostic categories are discussed herein.

Pure mucinous carcinoma of the breast

BACKGROUND

The lack of a standard definition of "pure" mucinous carcinoma of the breast has made it difficult to compare data from different studies. This study used the most stringent criteria to define parameters for truly pure lesions.

METHODS

Sixty-five patients were identified. The database was used to evaluate patients' demographics, tumor characteristics, and outcomes. Survival curves and predictors of survival were analyzed.

RESULTS

The mean age of presentation was 67 years. The majority (96%) of patients presented with early-stage disease. The 5- and 10-year overall survival rates were 93.6% and 72.8%, respectively. The number of involved axillary lymph nodes was the only significant predictor of death (P = 0.02).

CONCLUSIONS

Pure mucinous carcinoma of the breast has a favorable prognosis. Tumor size does not appear to impact survival, perhaps because the volume of mucin overestimates tumor burden. The number of involved axillary lymph nodes was the only significant predictor of death from disease.

Histochemical and immunohistochemical characterization of canine mammary mucinous carcinoma

Mucinous carcinoma is a rare mammary tumour, characterized by intracellular and extracellular mucin. It is still uncertain whether the origin of the mucin is epithelial, myoepithelial or fibroblastic. Eleven canine cases originally classified as mucinous carcinomas were reassessed and compared with myoepithelial nests of mixed tumours. All samples were examined (1) histochemically by the periodic acid-Schiff (PAS) and PAS-diastase methods, and with alcian blue (pH 2.5 and pH 1.0), mucicarmine and Grimelius silver stain, and (2) immunohistochemically for cytokeratin 19, vimentin, alpha-actin and chromogranin A. This examination revealed that only five of the 11 tumours were genuine mucinous carcinomas. In these five tumours the mucus-secreting cells showed cytoplasmic cytokeratin 19 positivity; the mucus showed PAS-diastase and mucicarmine positivity, and alcianophilia which was stronger at pH 2.5 than at 1.0. The remaining six cases were re-classified as mixed tumours because both mucus and mucus-producing cells shared the following similarities with myoepithelial nests of mixed tumours: vimentin and alpha-actin cytoplasmic positivity, PAS negativity, alcianophilia both at pH 2.5 and 1.0, and mucicarmine positivity.

Mucinous cystadenocarcinoma of the breast: a case report and review of the literature

We report a case of mucinous cystadenocarcinoma (MCA) of the breast in a 96-year-old woman. This is an extremely rare variant of primary breast carcinoma that bears a striking resemblance to MCAs of the ovary and pancreas. The macroscopic appearance and secretion pattern (cytologic findings) resembled cystic hypersecretory carcinoma. However, microscopically, the epithelial cells were quite different from those of cystic hypersecretory carcinoma. In the present study as well as in the literature, MCAs tend to occur more frequently in elderly women. Immunohistochemical findings suggest that they may develop independently of estrogenic stimulation. Although MCAs show high proliferative activity, the prognosis was favorable in the present case as well as in the reported cases. Because MCAs appear to have a distinct pathogenesis and biologic behavior, they should be distinguished from ordinary mucinous carcinomas, cystic hypersecretory carcinomas, and carcinomas of other histologic subtypes.

Breast carcinoma in women over the age of 85: distinct histological pattern and androgen, oestrogen, and progesterone receptor status

AIMS

The pathogenesis of breast carcinoma in very elderly women is of interest, because oestrogen levels are likely to be extremely low during the development of the disease. In an effort to understand the pathogenesis of breast carcinoma in these women, this study was undertaken to compare the histological patterns and hormone receptor status of breast carcinomas arising in very elderly and younger women.

METHODS AND RESULTS

Thirty-seven breast carcinomas from women over the age of 85 years at the time of their operation were examined histologically and compared with those from a large group of premenopausal women. The proportions of mucinous carcinoma and apocrine carcinoma were significantly greater in older women. The expression of steroid hormone receptors was studied immunohistochemically. Androgen receptor-positive carcinomas were significantly more frequent among older women, whereas progesterone receptor-positive carcinomas were significantly less frequent. There was no statistically significant difference in oestrogen receptor-alpha or -beta expression between the tumours from both groups.

CONCLUSION

Breast carcinomas in women over the age of 85 years have a different morphological spectrum from carcinomas in younger age groups and may have different pathogenesis mechanisms that may be more dependent on androgen and androgen receptor interaction. Differences from the results of the other studies are discussed.

Expression of cytokeratins 7 and 20 in carcinomas of the extrahepatic biliary tract, pancreas, and gallbladder

BACKGROUND

Expression of cytokeratins 7 (CK7) and 20 (CK20) may help distinguish the site of origin for metastatic carcinomas. Little is known regarding their expression in biliary tract and pancreatic carcinomas. Our aim was to study the expression of CK7 and CK20 in these tumors.

DESIGN

Fifty-three carcinomas of the extrahepatic bile ducts (n = 8), ampulla of Vater (n = 7), gallbladder (n = 11), and pancreas (n = 27), were retrieved from the surgical pathology files of the University of Massachusetts Medical Center. Formalin-fixed, paraffin-embedded sections were immunostained with mouse monoclonal antibodies to CK7 and CK20 using an avidin-biotin immunoperoxidase technique with microwave antigen retrieval. The percentage of cells positive for each antibody was assessed on a scale of 0 to 3 (0, <10%; 1+, 10% to 50%; 2+, 51% to 90%; 3+, >90%).

RESULTS

The majority of carcinomas in all groups were positive for CK7 (CK7+) and negative for CK20 (CK20-). Of the CK7+ tumors, the majority of tumors in each group were 3+ positive.

CONCLUSIONS

(1) Carcinomas of the extrahepatic biliary tract and pancreas are strongly positive for CK7 and negative for CK20 and can be included in the differential diagnosis of other carcinomas with this profile in metastatic sites. (2) The CK7/CK20 immunostaining profile will not identify the site of origin for tumors with extensive growth in the porta hepatis region.