Medullary carcinoma of the breast

Rare breast tumors: Review of the literature

Breast cancer tumors have different morphological phenotypes and specific histopathological types with particular prognostic and clinical characteristics. The treatment of rare malignant lesions is frequently controversial due to the absence of trials to determine the optimal managements. This review describes the spectrum of rare breast tumors indicating the clinical, epidemiological and treatment characteristics.

Management of Rare Histological Types of Breast Tumours

Breast tumours exhibit a wide range of morphological phenotypes, and specific histopathological types have particular prognostic and clinical characteristics. The management of uncommon premalignant and malignant lesions is often controversial due to the lack of large single-institution studies or randomised trials to define optimal treatments. In the era of frequent use of treatment guidelines, only a low level of evidence exists for the management of rare histological types of breast tumours. This review is divided into two parts: Firstly, the favourable histological subtypes like tubular, mucinous, medullary breast cancers, and phyllodes tumour (benign, borderline, and malignant) are discussed. The prognosis of these selected lesions is believed to be better than for invasive ductal carcinoma so that in some cases even less aggressive treatment should be considered. Patients with these specific histological types should be informed of this relatively favourable prognosis. Secondly, management recommendations for special situations like Paget's disease (tumour of the nipple) and inflammatory breast carcinoma are presented.

Colorectal carcinoma with dome-like phenotype: an under-recognised subset of colorectal carcinoma?

BACKGROUND

The term dome carcinoma has been applied to a variant of colorectal carcinoma, thought to derive from M-cells of the gut-associated lymphoid tissue. Its distinguishing morphological features include a non-polypoid plaque-like lesion composed of closely apposed cystically dilated glands lined by a single layer of non-mucinous cells, intensely PAS-positive intraluminal material, and a close spatial relation to lymphoid stroma.

AIMS AND METHODS

A search in the literature for such cases and the authors' experience with carcinomas sharing morphological details with dome carcinoma are presented to direct focus on this unique phenotype of colorectal carcinoma and to expand on its morphology.

RESULTS

Four such examples, all stage pT1, pN0 have been previously reported. Here two additional cases, with several features of dome carcinoma, stage pT1 and pT2, respectively, are added. An extensive intramucosal component, unassociated with adenomatous growth, a pink quality of the lesional cells, low grade budding, absence of cytoplasmic pseudofragments, and absence of necrosis characterised the present cases as well as intact MMR-proteins and loss of APC. As opposed to two of the previously reported cases, intraepithelial lymphocytes were unapparent in these cases and the lymphoid stroma was effaced along with tumour progression in one of the present cases. Hence, a range of appearances is encompassed by the dome carcinoma. The uncommon reporting of dome carcinoma may be due to lack of awareness of this particular subset of colorectal carcinoma. Indeed, one of the current cases was signed out as a conventional carcinoma, despite the comment in the pathology report of an unusual morphology.

CONCLUSION

Dome carcinoma may be more under-recognised than rare. The reporting of variants of colorectal carcinoma, displaying histological features suggestive of dome carcinoma, is encouraged in order to obtain more exact knowledge on its putative clinical significance.

Medullary carcinoma of the breast. Prevalence and prognostic importance of classical risk factors in breast cancer

In an earlier study of 235 breast cancers with medullary features, we concluded from a multivariate Cox regression analysis that only four histopathological features contained significantly positive prognostic information. In the present study, continuing our work on the same population base, we used these histological characteristics (predominantly syncytial growth pattern, no tubular component, diffuse stromal infiltration with mononuclear cells and sparse necrosis (< 25%), as diagnostic criteria for medullary carcinoma of the breast (MC). We found a significantly better prognosis for patients with MC than those with non-medullary carcinoma (NMC) or infiltrating ductal carcinoma (IDC). All tumours in the MC group were grade II or III (96% grade III). A significantly different distribution of general risk factors such as lymph node status, invasion, steroid receptor status, and menopausal status, was found between the group of MC and the control group of IDC grades II + III. Further, general risk factors, which are found to be of major prognostic importance in IDC, had little prognostic impact in MC. We found MC to be biologically unique, and patients with MC have a better than average prognosis compared to that of IDC. We propose a new histological definition of MC, but stress that prospective studies have to be performed.

Typical medullary carcinoma of the breast: a clinical and pathological analysis of 52 cases

Fifty-two women with typical medullary breast carcinoma, diagnosed according to criteria of Ridolfi et al. [Cancer 40:1365-1385, 1977] are described. At the time of diagnosis, 90% of the patients were stages I and II. The primary tumor size was < or = to 4 cm in 46 (88.5%) and > 4 cm in 6 (11.5%) patients. Axillary lymph nodes were microscopically negative in 35 (67.3%) and positive in 17 (32.7%) patients. All 52 women underwent the Patey operation. Seventeen patients with microscopically positive axillary lymph nodes received postoperative irradiation. Of the 52 treated patients, 44 (84.6%) survived 10 years NED. The only prognostic factor was the microscopical axillary lymph nodes status. In the group of pNO patients, 97.1% survived 10 years NED, pN+ 58.8% only. The sole causes of unsuccessful treatment were distant metastases to lungs, hepar, and bones. Typical medullary carcinoma is a favorable histological type of breast carcinoma with very good prognosis for pNO patients.

Medullary carcinoma of the breast: a tumour lacking keratin 19

The presence of keratin 19 (K19) was searched for by immunostaining in 16 medullary carcinomas, comprising 12 typical and four atypical cases, in 29 undifferentiated high-grade carcinomas (NOS-HG) with conspicuous lymphoid response and in 12 well differentiated low-grade carcinomas (NOS-LG). The medullary carcinomas were all negative whereas 23 of the high-grade and all 12 low-grade carcinomas expressed K19. Staining for K19 could be of value in the differential diagnosis of these tumours. Furthermore, these findings, with other observations, raise the possibility that medullary carcinoma cells could be linked to precursor cells of the terminal duct lobular units because both populations share several characteristics.

Medullary carcinoma of the breast, prognostic importance of characteristic histopathological features evaluated in a multivariate Cox analysis

In this study of 136 breast cancers with medullary features (MC), registered in the Danish Breast Cancer Cooperative Group (DBCG) from 1982 to 1987, we confirmed the prognostic importance of a new definition of medullary carcinoma of the breast (MC newdef) which was recently proposed by us, deduced from a previous study of a corresponding tumour material (DBCG 77-82). However, the individual histological criteria did not have the same prognostic importance as in our previous study, although prognostic trends were the same. To further improve and validate the diagnostic criteria, we combined the two populations and performed a multivariate Cox regression analysis. In the final Cox model, four histological parameters retained positive prognostic importance: (1) predominantly syncytial growth pattern, (2) no tubular component, (3) diffuse stromal infiltration with mononuclear cells and (4) sparse necrosis. We propose that these criteria are emphasized in the histological diagnosis of medullary carcinoma of the breast.

DNA ploidy and S-phase fraction in medullary carcinoma of the breast--a flow cytometric analysis using archival material

In a population of 110 primary breast cancers with medullary features, registered in the Danish Breast Cancer Cooperative Group (DBCG) from 1977-82, we have determined ploidy and S-phase fraction (SF) by flow cytometry (FCM) on paraffin embedded tumour tissue. The distribution of DNA ploidy is not different from the distribution described for breast cancers in general. No difference is found between the subgroups of medullary and non-medullary cancer when using a new simplified histopathological definition of medullary carcinoma of the breast, recently proposed by us. When using the definition proposed by Ridolfi et al. in 1977, we find significantly more tumours with aneuploidy and high SF in the groups of typical medullary carcinoma (TMC) and atypical medullary carcinoma (AMC) than in the small group of non-medullary carcinoma (NMC), which seems a paradox, as patients with NMC have the worst prognosis. However, the number of patients in the NMC group is very small, and the percentage of aneuploid tumours is very low. In 84 protocolled patients we found no statistically prognostic importance of ploidy or SF, either in the whole group assessed or when stratifying for the histopathological subgroups. However, a prognostic influence of SF can be traced for the non-medullary cancers, according to the new definition, but not for the medullary cancers of the breast. The result emphasizes the impression of MC as being biologically different from other histological types of breast cancer.

Pathological prognostic factors in breast cancer. II. Histological type. Relationship with survival in a large study with long-term follow-up

The histological tumour type determined by current criteria has been investigated in a consecutive series of 1621 women with primary operable breast carcinoma, presenting between 1973 and 1987. All women underwent definitive surgery with node biopsy and none received adjuvant systemic therapy. Special types, tubular, invasive cribriform and mucinous, with a very favourable prognosis can be identified. A common type of tumour recognized by our group and designated tubular mixed carcinoma is shown to be prognostically distinct from carcinomas of no special type; it has a characteristic histological appearance and is the third most common type in this series. Analysis of subtypes of lobular carcinoma confirms differing prognoses. The classical, tubulo-lobular and lobular mixed types are associated with a better prognosis than carcinomas of no special type; this is not so for the solid variant. Tubulo-lobular carcinoma in particular has an extremely good prognosis similar to tumours included in the 'special type' category above. Neither medullary carcinoma nor atypical medullary carcinoma are found to carry a survival advantage over carcinomas of no special type. The results confirm that histological typing of human breast carcinoma can provide useful prognostic information.

High endothelial venule and immunocompetent cells in typical medullary carcinoma of the breast

The characteristics of immunocompetent cells and their role in killing tumour cells in typical medullary carcinoma of the breast (TMC) have been investigated morphologically. Formation of high endothelial venule (HEV)-like vessels in tumour cell nests, the distribution of macrophages, T-zone histiocytes, T- and B-lymphocytes, the ratios of CD4+/CD8+, and natural killer (NK) or NK-like T-cells were examined in five cases of TMC. These results were compared with controls which consisted of three cases of ductal carcinoma with intense lymphocytic infiltration (control I) and four cases of ductal carcinoma with scanty lymphocytic infiltration (control II). An increased incidence of HEV-like vessels with migration of lymphocytes and a higher number of CD8+ lymphocytes with interleukin-2-receptor expression, as well as numerous CD57 cells, were noted in the tumour nests of TMC as compared with those of control groups. Furthermore, large granular lymphocytes, large lymphocytes invaginating tumour cells and necrotic tumour cells were observed electron microscopically. These findings indicate that infiltrating lymphocytes in TMC are activated and become effector cells that can kill the tumour cells by mechanisms similar to those of NK cells. The activities of immunocompetent cells in TMC appear to contribute to a favourable prognosis in TMC of the breast.

Outcome of conservative therapy for invasive breast cancer by histologic subtype

Between 1977 and 1986, 879 patients with Stage I and II breast cancer underwent excisional biopsy, axillary dissection, and radiation. Median follow-up was 61 months (range 2-159 months). The patients were divided into seven groups based on histologic subtype: (a) 368 patients with both infiltrating and intraductal ductal carcinoma, (b) 389 infiltrating ductal carcinoma, (c) 41 infiltrating lobular carcinoma, (d) 23 combined infiltrating ductal and lobular carcinoma, (e) 28 medullary carcinoma, (f) 12 colloid carcinomas, and (g) 18 tubular carcinomas. Significant differences in clinical T status, pathologic nodal involvement, administration of chemotherapy, estrogen receptor positivity, progesterone receptor positivity, and age were observed between some histologic subgroups. Tubular and colloid carcinomas were more likely to present with T1 lesions, hormone receptor positivity, and node negative status than the other histologic subtypes. Most medullary carcinomas were hormone receptor negative and were younger than 50 years old. Infiltrating lobular carcinoma patients were more frequently lymph node negative, older, node negative, and estrogen receptor positive compared to the other groups (except for tubular and colloid patients). Differences in the administration of chemotherapy primarily reflected differences in lymph node involvement. Location of the tumor in the breast and menopausal status did not correlate with histologic subtype. There were no significant differences in 5-year actuarial overall survival, cause-specific survival, or relapse-free survival between the histologic categories. In addition, patterns of first failure were not significantly different among the histologic groups in terms of local-only first failure, any local component of first failure, regional-only first failure, or any regional component of first failure. There was, however, a difference among the seven groups in distant metastasis-only at first failure with invasive ductal carcinomas having the highest rate. Despite this difference, histologic subtype had no impact on survival. The site of in-breast failure relative to the location of the original tumor was not significantly different between groups. The histologic subtype of invasive breast cancer is not an independent risk factor in predicting survival or pattern of failure. Conservative surgery and radiation therapy is effective treatment of ductal, lobular, medullary, colloid, and tubular invasive breast cancer.

Medullary carcinoma of the breast, proposal for a new simplified histopathological definition. Based on prognostic observations and observations on inter- and intraobserver variability of 11 histopathological characteristics in 131 breast carcinomas with medullary features

In a previous study of 131 breast carcinomas with medullary features, we evaluated the diagnostic inter- and intraobserver variation and its prognostic implications using the criteria of typical (TMC) and atypical (AMC) medullary carcinoma of the breast put forward by Ridolfi et al. (1977). We found a considerable interobserver variation as well as intraobserver variation, with significant implication on prognosis, and concluded that the histopathological definition of MC must be sharpened and simplified in order to increase the diagnostic reproducibility. In the present study of the same population of 131 patients with breast carcinomas with medullary features we have examined inter- and intraobserver variation concerning 11 histopathological characteristics. Furthermore, we have analysed the prognostic importance of these 11 histopathological features, and the prognostic implications of the observed inter- and intraobserver variation. Based on the observations, we have eliminated criteria with poor inter-/intraobserver agreement as well as those implying no or minimal impact on the prognosis. We propose a new simplified histopathological definition of medullary carcinoma of the breast (MC), retaining reproducible, prognostically significant criteria (syncytial growth pattern and diffuse, moderate or marked mononuclear infiltration). The prognosis of MC, based on this definition, is significantly better than those of infiltrating ductal carcinomas grade II + III.

Medullary cancer of the breast revisited

Common as well as unusual, heretofore unmentioned histopathologic features observed in 336 typical and 273 atypical medullary breast cancers from 6404 patients enrolled in various stage I and II protocols of the National Surgical Adjuvant Breast and Bowel Projects (NSABP) are presented. Both medullary types exhibited comparable pathologic findings, except for the infiltrative border and/or slight or absent tumor lymphoid infiltrate which by definition characterize the atypical form. Both also demonstrated a similar, high proclivity to be aneuploid, and to lack estrogen and progesterone receptors and nodal metastases. After appropriate statistical adjustments, survival (analyzed for 198 patients with typical and 149 with atypical medullary cancers) was found to be better for untreated, node-negative and node-positive patients treated with L-PAM + 5Fu who had typical medullary cancers than those with the NOS histologic type. The magnitude of this difference was 6% at 5 and 17% at 10 years post-operatively (cumulative odds = 1.81 with a 95% confidence interval of 1.08 - 3.3) for the former group, and 4% at 5 and 16% at 10 years (cumulative odds = 1.56 with a 95% confidence interval of 1.08 - 2.23) for the latter. Survival was comparable for patients with atypical medullary and NOS types in both situations. No clear difference in survival was found in untreated, positive node patients with the 3 histologic types examined, although the sample sizes in this subset were relatively small. This information as well as other pertinent considerations indicate that the prognosis of typical medullary cancer is not as 'good' as previously perceived. It is also concluded that there is insufficient evidence at present to exclude the atypical medullary variant as a histologic type of breast cancer.

The prognostic importance of syncytial growth pattern in medullary carcinoma of the breast

The histopathological criteria for medullary carcinoma of the breast (MC) used by most pathologists today were delineated by Ridolfi et al. in 1977. The prime criterion is: "A predominantly syncytial growth pattern", predominantly being defined as including 75% or more of the tumour. However, no indication has been given as to why this limit was set at 75%. The present study analyzes the prognostic importance of the extent of syncytial growth in a population of 102 breast cancers with medullary features. Generally, we find a positive prognostic influence of an extensive syncytial growth. The prognostic importance of setting the limit for predominantly syncytial growth at 90% and at 75%, respectively, is evaluated. This comparative study provides no basis for changing the definition of predominantly syncytial growth pattern.