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.     

Immunohistochemical comparison between GCDFP-15 and estrogen and progesterone receptors in the diagnosis of metastatic carcinoma of the breast

Background: in the workup of tumors of unknown primary origin in women, a frequent consideration is breast carcinoma, because it is common and may initially present as metastasis. Objective: describe and compare the immunohistochemical profile of hormonal receptors (estrogen receptor and progesterone receptor) and GCDFP-15 in lymph node metastatic breast carcinoma according the histological grade. Methods: retrospective study analyzing 30 patients with identified primary breast cancer and lymph node metastasis. The cases were divided in three groups: grade I (well differentiated), grade II (moderately differentiated) and grade III (poorly differentiated). We used three antibodies (estrogen receptor, progesterone receptor and GCDFP-15) in the lymph node and compare the expression according the histological grade. Results: in metastatic lymph node from grade I breast carcinomas the hormone receptors were 100% positive and GCDFP-15 was 80% positive. In grade II, estrogen receptor and progesterone receptor were positive in 90 and 40% respectively, and GCDFP-15 was positive in 80%. In grade III, estrogen receptor and progesterone receptor were positive in 30 and 50% respectively, and GCDFP-15 in 60%. Conclusions: the immunohistochemical expression of hormonal receptors and GCDFP-15 in metastatic breast carcinoma is related to histological grade in the breast.     

乳腺实体型乳头状癌的临床病理研究

目的探讨乳腺实体型乳头状癌（SPC）的临床病理特征和免疫表型特点。方法收集伴或不伴有浸润癌的SPC共21例,总结其临床资料、大体和组织病理特征,并进行免疫组织化学LSAB法染色和阿辛蓝黏液染色。选用抗体包括细胞角蛋白（CK）、肌上皮标记、神经内分泌标记、增殖标记Ki-67和雌激素受体（ER）、孕激素受体（PR）等。结果本组患者均为女性,发病平均年龄66．1岁。肿瘤的临床特征与经典型乳头状肿瘤相似。行腋窝淋巴结清扫术的8例中无1例检出癌转移。镜检所有标本均见到实体乳头状病变,19例存在黏液分泌。肿瘤细胞呈卵圆形、多角形、梭形或旱印戒样。细胞为轻度或中度异型性,15例核分裂象〈5／10HPF。7例伴发细胞学与导管内癌一致的浸润癌。肿瘤均表达CK8,但基底型CK呈阴性。平滑肌肌动蛋白（SMA）d、Calponin和p63在乳头轴心肌上皮的阳性率分别为94．0％、64．7％和58．8％,在导管周缘肌上皮的阳性率分别为94．0％、76．5％和70．6％。CgA和突触素阳性率分别为88．2％和82．4％。Ki-67平均阳性指数为8．1％。17例行ER、PR和pS2染色的肿瘤均呈阳性,c—erbB-2均阴性。获得随访的患者中16例（94％）均未见肿瘤复发或转移。结论乳腺SPC好发于老年女性,具有较独特的病理组织学改变和免疫表型,部分SPC与乳腺黏液癌和神经内分泌癌相关。多项临床病理特征和随访显示SPC具有较为惰性的生物学行为和良好的预后。     

Solid-papillary carcinoma of the breast: clinicopathological study of 20 cases

The purpose of the present paper was to evaluate the clinicopathological and biological features of 20 Japanese patients with solid-papillary carcinoma of the breast (SPC) or SPC associated with invasive breast cancer. All the patients were Japanese women, including two sisters. The mean age was 66.0 years. The incidence of SPC among all the breast cancers treated at two institutions was 1.1% and 1.7%, respectively. The mean disease-free interval was 4 years 11 months. Axillary lymph node metastasis or tumor recurrence did not occur in any of the cases. Fifteen cases of SPC contained invasive cancers that ranged from <5% to 60% of the entire tumor area. Histological types of invasive cancers were mucinous carcinoma in five cases and neuroendocrine cell carcinoma in 10 cases. These results indicate that SPC is a potential precursor lesion for neuroendocrine carcinoma as well as mucinous carcinoma. When all the cases were classified and analyzed according to both the 2002 tumor node metastasis (TNM) classification system and the Nottingham histological grade, SPC patients, even those with invasive cancers, seemed to have longer disease-free survival compared to patients with the other invasive breast cancers of matching grade and stage. Clinicopathologically, SPC could be regarded as a separate type of ductal carcinoma in situ.     

Distribution of laminin,type IV collagen and fibronectin in the invasive component of breast carcinoma

Laminin, type IV collagen and fibronectin were examined immunohistochemically in the invasive component of breast carcinomas. Laminin was expressed around the invasive carcinoma cell nests in 38 (54%) of 71 cases. Immunoreactiv-ity for type IV collagen was observed around the invasive carcinoma cell nests or the stroma apart from carcinoma cells in 44 (80%) of 55 cases. Fibronectin was strongly expressed in the stroma only in 75 (99%) of 76 cases. The expression of laminin significantly correlated with tubular formation in the invasive carcinoma cell nests and showed a tendency to be correlative to estrogen receptor (ER) and progesterone receptor (PgR) of carcinoma tissue, but no correlation among laminin expression, histological type, the age of patients, tumor size and lymph node metastasis was noted. Type IV collagen and fibronectin did not correlate to any clinicopathological factors such as histological type, grade of differentiation, the age of patients, tumor size, lymph node metastasis, ER and PgR status. No concordant expression of these extracellular matrices was seen.     

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.     

Ductal carcinoma in situ with spindle cells: a potential diagnostic pitfall in the evaluation of breast lesions

AIMS: To evaluate the morphological features of 11 cases of breast ductal carcinoma in situ (DCIS) with spindle cells and to propose an approach to distinguish it from benign mimics. The association with neuroendocrine differentiation was also investigated. METHODS: Cases of breast DCIS with a spindle cell component diagnosed in the Department of Pathology, Singapore General Hospital, between June 1996 and January 2003, were included in the study. The histological characteristics were documented, and immunohistochemistry for neuroendocrine markers, hormone receptors, cerbB2, smooth muscle actin (SMA) and high-molecular-weight (HMW) cytokeratins, was carried out. Electron microscopy was carried out on reprocessed paraffin-embedded material in three cases. RESULTS: Of 11 women diagnosed with DCIS with spindle cells, four presented with nipple discharge, six with a breast lump, while one was discovered to have a screen detected density. The tumour size ranged from 3 to 41 mm. The proportion of spindle cells varied from 10% to 80% of the in-situ tumour cell population. Nuclear grade was low in seven cases and intermediate in four. Necrosis was observed in two cases. Architectural pattern was papillary in six cases, and mixed in the rest. Microinvasion was present in two cases, with possible microinvasion in another two. Immunohistochemistry for neuroendocrine markers synaptophysin and chromogranin showed positive reactivity for at least one marker in all but three cases; one of these latter cases demonstrated ultrastructural neurosecretory granules. Oestrogen and progesterone receptors were expressed in 10 and nine cases, respectively, while cerbB2 was positive in only one case. HMW cytokeratin immunoprofile revealed a general lack of immunostaining within the abnormal cell population; likewise, no positivity for SMA of the cellular proliferation was detected. CONCLUSIONS: Almost all DCIS lesions with spindle cells disclose neuroendocrine differentiation. Although the distinction from benign florid usual hyperplasia may pose a diagnostic histological problem, the presence of diffuse neuroendocrine expression, in conjunction with the pattern of HMW keratin profile on immunohistochemistry, supports an in-situ neoplastic process. The absence of SMA immunostaining, in conjunction with negative reactivity for cytokeratins 5/6 and 14, makes the possibility of a myoepithelial proliferation unlikely.     

A case of primary mucinous carcinoma with endocrine differentiation of the skin

Primary mucinous carcinoma of the skin (MCS) is a rare skin appendage tumor and only a few cases of MCS with endocrine differentiation have been reported. Here we report an additional case of primary pure MCS with endocrine differentiation arising in the face. Histopathologically, the tumor was located in the dermis and subcutis, and nests of slight atypical epithelial cells were floating in the mucinous pools. This tumor did not accompany carcinoma in situ or invasive non-mucinous carcinoma and was difficult to differentiate from metastatic mucinous carcinoma of the skin. There was no tumor in the other organs and synaptophysin and chromogranin A were sporadically shown immunohistochemically in the tumor cells; a diagnosis of primary pure MCS with endocrine differentiation was made. MCS resembles mammary mucinous carcinoma not only in morphological appearance but also in immunohistochemical phenotypes, such as positive immunoreactivity to gross cystic disease protein fluid-15, MUC2, MUC6, estrogen receptor and progesterone receptor. It is presumed that MCS is derived from the apocrine gland, which is closely related to the mammary gland. Although endocrine differentiation is not uncommon in pure mucinous carcinoma of the breast, there have been only a few reports published on endocrine differentiation in MCS. To clarify the difference and/or similarity between mucinous carcinoma of the breast and MCS, immunohistochemical and cytogenetic analyses of additional cases of MCS are required.     

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.     

Mucinous breast carcinomas with abundant intracytoplasmic mucin and neuroendocrine features: light microscopic, immunohistochemical, and ultrastructural study

Eight mucinous carcinomas of the breast were studied by light microscopy and immunohistochemistry; one was studied by electron microscopy. All 8 cases had abundant, relatively clear cytoplasm that contained mucin. Cells were argyrophil positive and argentaffin negative. Eight cases were positive for neuron specific enolase (NSE), 5 cases for serotonin, 1 case for serotonin and somatostatin and 2 cases for serotonin, somatostatin, and gastrin. None had clinical evidence of abnormal neuroendocrine function. Three patients had axillary lymph node metastases. Only 1 of 5 patients in whom there was clinical followup died of her disease. Electron microscopy of one case showed abundant intracytoplasmic and extracellular mucin, round and pleomorphic dense-core granules, numerous cell processes, and aggregates of intermediate filaments. These cases expand the histologic spectrum of breast carcinomas which may show neuroendocrine differentiation.     

乳腺癌组织中uPA、uPAR及nm23-H1的表达

目的　观察乳腺癌组织中uPA、uPAR、nm2 3 H1的表达并探讨与腋窝淋巴结转移的关系。方法　用免疫组化EnVi sion两步法检测 6 9例乳腺癌组织中uPA、uPAR和nm2 3 H1表达的分布情况 ,观察其与肿瘤的分化程度以及与腋窝淋巴结转移的关系。结果　 (1)uPA阳性表达定位于癌细胞胞质 ;uPAR和nm2 3 H1阳性表达定位于癌细胞胞膜及胞质 ,多数癌旁乳腺上皮细胞呈nm2 3 H1阳性表达 ;高分化乳腺癌 (Ⅰ级 )uPA和uPAR表达阳性率 (30 0 %和 2 5 0 %)低于中低分化乳腺癌 (Ⅱ、Ⅲ级 ) (分别为 6 8 1%、72 7%和 70 0 %、74 1%) (P <0 0 5 ) ;nm2 3 H1表达阳性率在乳腺癌组织不同分化程度间差异无显著性 (P >0 0 5 ) ;(2 )腋窝淋巴结有转移者uPA和uPAR的表达阳性率 (73 2 %和 75 6 %)高于无淋巴结转移者 (35 7%和35 7%) (P <0 0 5 ) ;有腋窝淋巴结转移者nm2 3 H1的表达阳性率 (2 4 4 %)显著低于无淋巴结转移者 (5 0 0 %) (P <0 0 5 ) ;uPA、uPAR和nm2 3 H1的表达与淋巴结转移的个数均无关 ;(3)uPA阳性表达的癌组织其nm2 3 H1表达阳性率 (15 0 %)低于uPA阴性表达的癌组织 (6 2 1%) (P <0 0 5 )。结论　uPA和uPAR的高表达与乳腺癌腋窝淋巴结转移密切相关 ;uPA、uPAR和nm2 3 H1可以作为乳腺癌侵袭与淋巴结转移的     

Invasive micropapillary carcinoma of the breast: clinicopathological and immunohistochemical study

Invasive micropapillary carcinoma (IMPCa) of the breast refers to a unique variant of invasive ductal carcinoma, but its biological behavior has not been elucidated well. We analyzed 16 IMPCa cases (10 pure type, six mixed type). The incidence of IMPCa was 1.0% of all primary breast carcinoma. High nuclear grade (75.0%), as well as poorly differentiated histological grade (81.3%), was frequently seen. Lymph node metastases were evident in 92.9% of the examined cases, and about half of them showed more than 10 positive nodes. Comparison between serially experienced invasive ductal carcinoma, not otherwise specified (IDC-NOS), revealed that both high nuclear grade and poor histological grade were significantly more frequent ( P  < 0001), there was a lower frequency of positive estrogen receptor/progesterone receptor ( P  < 0.05, P  < 0.01), a higher frequency of HER-2 overexpression ( P  < 0.025), and more frequent lymph node metastases ( P  < 0.05) in IMPCa. The comparison between lymph node positive IDC-NOS did not show any statistically significant differences in frequency for positive p53, matrix metalloproteinase protein-2 (MMP-2), vascular endothelial growth factor (VEGF) or E-cadherin. However, IMPCa showed a significantly increased number of blood vessels counted by CD34 immunostains ( P  < 0.05). These results suggest that IMPCa is, at least, the same or more aggressive than lymph node positive cases of IDC-NOS. Hence, not only the high incidence of lymph node metastases but also distant, blood-borne metastases may be important.     

Mucinous breast carcinoma metastatic to thyroid gland: Report of a case diagnosed by fine‐needle aspiration cytology

Mucinous breast cancer is a slow‐growing neoplasm, which has fewer lymph node metastases and favorable prognosis compared with invasive breast cancer no special type. The hematogenous spread of breast mucinous carcinoma is very rare. Though breast cancer involving thyroid has been reported before, there is still no report about thyroid metastatic breast mucinous carcinoma in the literature. Recently by performing thyroid fine‐needle aspiration, a 58‐year‐old woman who had breast cancer 13 years ago was diagnosed as thyroid metastatic mucinous breast carcinoma, cellular variant with neuroendocrine differentiation. For this patient, the thyroid was the only involved site without widespread metastatic diseases, so thyroidectomy and the right cervical lymph nodes dissection were performed to make better survival. As a result, the patient had not shown any signs of recurrence 9 months after the thyroid surgery.     

Prognostic factors in primary mucinous breast carcinoma

Two hundred seven mucinous breast carcinomas were morphologically classified into two different groups: pure mucinous carcinomas consisting only of areas with small epithelial islands of solid tumor floating in abundant extracellular mucin, and mixed carcinomas where the tumor contains large areas of mucin, as well as areas with infiltrating carcinoma devoid of extracellular mucin. Of the 207 tumors, 95 were of the pure type and 112 of the mixed type. The pure and mixed carcinomas differed significantly with respect to a number of prognostic factors, the most important of which was lymph node status. Patients with pure mucinous carcinomas had significantly fewer lymph node metastases at the time of primary operation (P = 0.0001) and a significantly longer recurrence-free survival (P = 0.03) than patients with mixed carcinomas. Patients with mixed carcinomas closely resembled patients with infiltrating ductal carcinomas not otherwise specified (NOS) with respect to both lymph node status and recurrence-free survival. In multivariate analysis, the single most important factor for predicting recurrence-free survival among the 207 patients was lymph node status. However, of 94 pure carcinomas, only 6 had lymph node metastases at the time of mastectomy. A detailed morphologic analysis demonstrated that two of these six cases were incorrectly diagnosed as being pure mucinous carcinomas--they were actually of the mixed type. In another two of these cases, the metastases originated from a co-existent infiltrating ductal carcinoma. Thus, metastases to the regional lymph nodes were observed in only two cases of pure mucinous carcinomas. It is concluded that the biologic behavior of the pure mucinous carcinomas differs from that of both the mixed carcinomas and infiltrating ductal carcinomas NOS. Thus, a new definition is suggested, in which a mucinous carcinoma is classified as such only if it is a pure carcinoma, and mixed mucinous carcinomas are classified according to the component without extracellular mucin production.     

Epithelial inclusion in axillary lymph node associated with a breast carcinoma: report of a case with a review of the literature.

Since epithelial inclusions in axillary lymph nodes are rare, some diagnostic problems concerning their nature have arisen. We report a case of a cystic squamous epithelial inclusion in an axillary lymph node of a patient affected by a high grade breast carcinoma with focal squamous differentiation. Although the lesion was histologically benign, the possibility that it represents a well-differentiated squamous metastasis cannot be completely ruled out. To our knowledge, this is the first case of an epithelial lymph node inclusion associated with a breast carcinoma showing morphological evidence of squamous differentiation. Here, we discuss the diagnostic problems and give a review of the literature.     

Primary neuroendocrine small cell carcinoma of the breast

A 60-year-old Turkish woman presented with a left breast mass, which was considered for neoadjuvant chemotherapy. By the end of the treatment cycles, the tumor had decreased in size, and the patient underwent modified radical mastectomy with axillary lymph node dissection. Pathologic examination of the tumor revealed a small cell carcinoma with neuroendocrine features confirmed by immunohistochemical stains. Multiple axillary lymph nodes were involved by metastatic small cell carcinoma carrying the same morphologic characteristics noted in the primary breast tumor. We hereby present this case as a primary neuroendocrine small cell carcinoma of the breast. This entity occurs very rarely in the breast, and fewer than a dozen cases have been reported in the literature. Extrapulmonary small cell carcinoma of the breast is reportedly a very aggressive tumor for which no consensus for treatment has yet been drawn.     

Relationship between the expression of various markers and prognostic factors in breast cancer

The immunohistochemical detection of six markers of breast cancer has been compared in the present study with known prognostic factors of the disease to establish locally a standard panel of markers for the management of breast cancer. Sections of tissue of 114 consecutive breast cancer cases were studied immunohistochemically, using antibodies against oestrogen receptor (ER), progesterone receptor (PR), androgen receptor, c-erbB2, cathepsin D, and cyclin D. Marker labelling was graded as recommended in the literature. Using the chi(2)-test, relationships were determined between marker labelling and histological type of cancer, tumour grade, tumour size, axillary lymph node status and age of patient. A p value below 0.05 was considered significant. A positive relationship was found between ER and PR and lower grades of cancer, and a negative relationship was found with medullary and atypical medullary carcinoma. The four other markers showed no relationship with grade or type of cancer. All markers showed no significant relationship with size of tumour, presence of axillary node metastasis or age of patient. There was positive correlation between c-erbB2 and cathepsin D. Our study confirms the association between ER and PR and histological type and grade of breast cancer, both known parameters of good prognosis. We found no consistent relationship between the other four markers and prognostic factors studied, other than the suggestion that c-erbB2 and cathepsin D may be useful markers for poor prognosis and can be usefully applied locally, especially in the light of the current availability of trastuzumab (Herceptin) for management of c-erbB2-positive cases. We found no relationship between the markers and tumour size, axillary lymph node status or age.     

Neuroendocrine Tumors of the Breast

A small but increasingly recognized and studied subset of breast carcinomas are characterized by neuroendocrine (NE) differentiation. As with nearly all forms of breast neoplasia, NE tumors are characterized by considerable heterogeneity in microscopic appearance and clinical aggressiveness. About half of NE breast carcinomas recapitulate the histological spectrum typical of their counterparts in other organ systems, varying from “carcinoid-like” to small cell carcinoma, with most representing intermediate grade tumors. Despite NE morphology, these tumors have a high frequency of estrogen receptor expression. Clinical outcomes of women with NE breast carcinomas are reliably grade and stage dependent. Tumors associated with “solid papillary” differentiation comprise the remaining cases of NE breast neoplasia. Solid papillary carcinoma is an intrinsically low grade/favorable prognosis class of breast neoplasia that usually presents in post-menopausal age groups. About half of solid papillary carcinoma present as a distinctive pattern of ductal carcinoma in situ that may be difficult to recognize owing to its close resemblance to florid proliferative lesions. Invasive solid papillary carcinomas are characterized by a variety of histological patterns and often show mucinous differentiation. Future studies are necessary to better define the histogenesis, optimal classification, and improved directed therapies for NE breast neoplasia.     

The significance of c-erbB-2 overexpression and p53 expression in patients with axillary lymph node--negative breast cancer: a tissue microarray study

We conducted this study to examine whether the expression of c-erbB-2 and p53 is the prognostic indicator for patients with early-stage breast cancer in which axillary lymph node metastasis is absent. We examined 326 patients with early-stage breast cancer in which axillary lymph node metastasis is absent. Tissue microarrays were constructed. Following this, immunohistochemical staining was done for estrogen receptor (ER), progesterone receptor (PR), c-erbB2, and p53. The results were as follows: (1) expression of c-erbB-2 was correlated with other clinicopathologic factors (eg, patient's age, presence of menopause, tumor size, histologic and nuclear grade, and presence of hormone receptors such as ER and PR); and (2) expression of p53 was correlated with survival rate, patient's age, presence of menopause, and tumor size. However, these results were not statistically significant. In conclusion, our results indicate that expression of c-erbB-2 and p53 did not have any prognostic value in patients with early-stage breast cancer in which axillary lymph node metastasis is absent.     

Metaplastic carcinoma of the breast: a clinicopathological review

BACKGROUND: Mammary metaplastic carcinoma encompasses epithelial-only carcinoma (high-grade adenosquamous carcinoma or pure squamous cell carcinoma), biphasic epithelial and sarcomatoid carcinoma and monophasic spindle cell carcinoma. AIM: To evaluate the clinicopathological features of a large series of 34 metaplastic carcinomas. METHODS: 10 epithelial-only, 14 biphasic and 10 monophasic metaplastic carcinomas were assessed for nuclear grade, hormone receptor status, HER2/neu (cerbB2) oncogene expression, Ki-67 and p53, lymph node status and recurrence on follow-up. RESULTS: Intermediate to high nuclear grade were assessed in most (33/34) tumours. Oestrogen and progesterone receptors were negative in 8 of 10 epithelial-only, all 14 biphasic, and 9 of 10 monophasic tumours, cerbB2 was negative in 7 of 10 epithelial-only, all 14 biphasic and 8 of 10 monophasic tumours. Ki-67 was found to be positive in 6 of 10 epithelial-only, 6 of 14 biphasic, and 7 of 10 monophasic tumours, whereas p53 was positive in 6 of 10 epithelial-only, 7 of 14 biphasic, and 8 of 10 monophasic tumours. Lymph node metastases were seen in 7 of 7 epithelial-only, 7 of 11 biphasic, and 3 of 7 monophasic tumours. Recurrences were seen in 4 of 7 epithelial-only, 8 of 9 biphasic, and 4 of 9 monophasic tumours. CONCLUSIONS: All three subtypes of metaplastic carcinoma are known to behave aggressively, and should be differentiated from the low-grade fibromatosis-like metaplastic carcinoma, which does not metastasize. Oncological treatment options may be limited by the frequently negative status of hormonal receptor and cerbB2.