Fibroadenomas of the breast with prominent smooth muscle

Breast Cytology and Pathology in Pregnancy and Lactation

Breast tissue reveals some physiologic changes during pregnancy and lactation due to hormonal alterations. Whole range of breast diseases including inflammatory, benign and malignant neoplasms can be seen in pregnancy but due to concurrent physiologic changes, may lead to diagnostic challenges. This chapter reviews sampling methods and histologic features of common benign breast lesions in pregnancy and lactation periods.

Muscular Hamartoma of the Breast

A case of a muscular hamartoma of the breast in a 47-year-old woman is presented. Tumors containing smooth muscle are rare in the breast. Radiologically it appears as a circumscribed tumor with homogeneous or varying density. Histologically these lesions are composed of ducts, lobules, stroma prominently adipose, and smooth muscle.

Significance of rat mammary tumors for human risk assessment

We have previously indicated that the ideal animal tumor model should mimic the human disease. This means that the investigator should be able to ascertain the influence of host factors on the initiation of tumorigenesis, mimic the susceptibility of tumor response based on age and reproductive history, and determine the response of the tumors induced to chemotherapy. The utilization of experimental models of mammary carcinogenesis in risk assessment requires that the influence of ovarian, pituitary, and placental hormones, among others, as well as overall reproductive events are taken into consideration, since they are important modifiers of the susceptibility of the organ to neoplastic development. Several species, such as rodents, dogs, cats, and monkeys, have been evaluated for these purposes; however, none of them fulfills all the criteria specified previously. Rodents, however, are the most widely used models; therefore, this work will concentrate on discussing the rat rodent model of mammary carcinogenesis.

Myoid hamartoma of the breast that proved difficult to diagnose: a case report

Myoid hamartomas of the breast are extremely rare breast lesions, with a poorly understood pathogenesis. We describe the case of a 38-year-old premenopausal woman who presenting with a mass in the left breast. Mammography revealed an oval mass that was partly indistinct, and ultrasonography showed a hypoechoic mass with a slightly irregular margin. Bilateral breast dynamic magnetic resonance imaging was performed for a more detailed evaluation. The images showed rapid initial enhancement and a microlobulated margin. Because the suspicion of malignancy was strong at that time, core needle biopsy was performed. Histologically, the tumor was identified as fibroadenoma. A case of myoid hamartoma of the breast that proved difficult to diagnose is reported, and discussed with reference to the literature.

Aggressive giant fibroepithelial lesion with unusual vascular stroma--a case report

The stroma of fibroadenoma and phyllodes tumor usually consists of fibroblastic proliferation. Rarely the stroma contains bundles of smooth muscle. Pseudoangiomatous hyperplasia of the mammary stroma has been described in fibroadenomas. However, true benign vascular stroma has not been reported. We report a case of a 34-year-old Chinese woman who presented with a large mass occupying the entire left breast. Left mastectomy was performed and showed a large, well-circumscribed, lobulated, rubbery-firm tumor measuring 13 x 10 x 6 cm. Microscopic examination revealed a fibroepithelial tumor formed by an organoid pattern of ductal structures with a very striking stromal appearance composed of extensive vascular proliferation and that demonstrated strong immunoreactivity for CD31, CD34, and Factor VIII. Ultrastructural examination revealed intercellular junctions, basal lamina, pinocytotic vesicles, and Weibel-Palade bodies in the cells lining the vascular spaces, confirming their endothelial nature. These findings rule out the diagnosis of pseudoangiomatous hyperplasia. The patient developed local recurrence a year later, and the resection showed malignant phyllodes tumor with ductal carcinoma in situ. The extensive vascular stroma noted in the primary tumor may have played a role in the malignant transformation of the epithelial and stromal components in this tumor.

Benign spindle cell tumors of the mammary stroma: diagnostic criteria, classification, and histogenesis

Purely benign mesenchymal spindle cell neoplasms of the breast are currently labeled under various terms in the literature (benign spindle cell tumor, fibroma, spindle cell lipoma, myofibroblastoma, solitary fibrous tumor, myogenic stromal tumor). The lack of strict diagnostic criteria to clearly indicate such mesenchymal neoplasms is the main reason which generated the risk of terming the same lesion under different names or, conversely, of collecting different types under the same term. Although such neoplasms exhibit morphological and immunophenotypical heterogeneity, they actually represent variations of the same tumor entity, likely arising from the uncommitted vimentin+/CD34+ fibroblasts of the mammary stroma, capable of multidirectional mesenchymal differentiation. To cover the entire spectrum of such lesions, the term "benign spindle cell tumors (BSCTs) of the mammary stroma" is advocated. BSCTs can be subtyped into four main groups by light microscopy (LM) and immunocytochemistry (ICC): fibroblastic, myofibroblastic, fibrohistiocytic, and mixed forms. A simple and practical approach to a nosologically correct diagnosis and a list of differential diagnoses are presented. The awareness of the diversity of morphological and immunophenotypical features of BSCTs of the mammary stroma, including uncommon variants, is helpful to avoid confusion with other monomorphic bland-looking benign and malignant spindle cell tumors and tumor-like lesions of the breast.

No elevation in long-term breast carcinoma risk for women with fibroadenomas that contain atypical hyperplasia

BACKGROUND

The authors previously showed that women with a fibroadenoma have a relative risk of invasive breast carcinoma of approximately 2.0 compared with women of similar age from the general population. This relative risk approaches 1.0 when family history and proliferative changes in the adjacent parenchyma are removed and rises to > 3.0 if the fibroadenoma has complex histology. The risk for developing breast carcinoma in women with atypical lobular hyperplasia (ALH) and atypical ductal hyperplasia (ADH) or their minimal variants within a fibroadenoma is unknown.

METHODS

The authors conducted a long-term, retrospective cohort study of 1834 women with adequate follow-up who presented with fibroadenoma at three local hospitals between 1950 and 1968. Histology was reviewed using established criteria, and the patients were categorized with ALH, ADH, minimal atypia, or no atypia.

RESULTS

The overall prevalence of ALH or ADH within fibroadenomas was 0.81%. Minimal or true atypia within a fibroadenoma appeared to be correlated with proliferative disease in the adjacent parenchyma but could not predict for the presence there of well-established atypia. Only 7% of women with well-developed atypia developed invasive carcinoma on follow-up. Three women with minimal atypia developed invasive carcinoma.

CONCLUSIONS

In this study of a large cohort of women with fibroadenoma, the authors found that atypia within a fibroadenoma cannot predict for the presence of atypia within adjacent breast parenchyma. They also found that atypia confined to a fibroadenoma does not incur a clinically meaningful risk of future breast carcinoma development greater than that of fibroadenoma alone.

Proliferative activity and tumor angiogenesis is closely correlated to stromal cellularity of fibroadenoma: proposal fibroadenoma, cellular variant

Fibroadenoma (FA) is the most common benign tumor of the breast in adult women. Some FA have a highly cellular stroma, making it difficult to differentiate from phyllodes tumors (PT). Forty-three FA were grouped into: (i) 27 conventional type (FACT) median stromal cellularity (SC) of highest cellular area (HCA), < or = 125 cells/1 high-power field (HPF); and (ii) 16 cellular variant (FACV) median SC of HCA, > 125 cells/1 HPF. These were studied for the proliferative activity of their stromal cells. Expression of c-fos, p53, basic fibroblast growth factor (bFGF), fibroblast growth factor receptor (FGFR), and vascular endothelial growth factor (VEGF) in the stromal cells were examined in the FA and 12 PT to determine whether it is possible to separate FACV from FACT. The proliferative activity of stromal cells was evaluated by the labeling index (LI) of proliferating cell nuclear antigen (PCNA). Conventional type fibroadenoma stromal cells had the lowest frequency of c-fos, p53, bFGF, FGFR and VEGF protein expression; PT stromal cells had the highest frequency of expression; and FACV stromal cells had an intermediate frequency of expression. Multivariate analysis demonstrated that bFGF and FGFR expression are significantly correlated with SC of FA. Separation of FACV from FACT by SC seems appropriate in revealing the phenotypic and biological differences of FA. The SC of FA seems to be regulated by bFGF and FGFR expression.

Muscular hamartoma of the breast. Case report and review of the literature

Muscular hamartoma (MH) is a rare tumor-like lesion of the breast, and only 22 cases have been reported in the literature. We report an additional case of MH of the breast, giving a new immunocytochemistry-based insight into the histogenesis of the smooth muscle component. The expression of CD34 antigen in smooth muscle cells suggested that MH originates from stromal cells via leiomyomatous metaplastic changes. This hypothesis was supported by the evidence that stromal cells in the normal parenchyma nearby the hamartoma were positive for CD34 antigen and, focally, also positive for smooth muscle markers (alpha-smooth muscle actin and desmin). A complete list of differential diagnoses and a review of the literature on the topic are provided. Although the use of the term "muscular hamartoma" could be considered inappropriate because of the absence of smooth muscle tissue in the normal breast, the authors underline that this designation can be easily accepted if the histogenesis of the heterologous component is regarded as a result of a stromal cell metaplastic change.

Histopathological study of stromal smooth muscle cells in fibroadenoma of the breast

Smooth muscle cells are extremely rare stromal components of fibroadenoma. Eighty-five cases of fibroadenoma were reviewed in order to investigate the frequency of smooth muscle cells and to discuss its origin. Of the 85 cases, four (4.7%) cases showed smooth muscle cells in the stroma. Distribution in terms of age and tumor size did not show any difference from other cases. Three cases were classified as an intracanalicular subtype, and one was a mastopathic subtype. The cells possessed most of the ultrastructural characteristics of smooth muscle cells, but poor indentation of nuclear contours suggested the last remnant of fibroblasts. It was therefore easy to recognize the cells derived from fibroblasts. In two of four cases, smooth muscle cells were observed in the stroma, which had marked hyalinization and calcification. Therefore, it was supposed that smooth muscle cells could appear in the stroma of long-standing tumors.

Antigenic profile of mammary fibroadenoma and cystosarcoma phyllodes. A study using antibodies to estrogen- and progesterone receptors and to a panel of cell surface molecules

Using serial frozen sections, monoclonal antibodies and an indirect immunoperoxidase method, 13 fibroadenomas (FA) and 3 cystosarcomas phyllodes (CSP) were analyzed for the expression of Egp34, HEA319-antigen, leucocyte differentiation antigens CD10, CD30, CD57, CD72, CDw75, and CD77, epidermal growth factor receptor (EGFR), estrogen (ER) and progesterone receptor (PR), and transferrin receptor (CD71). Egp34, CDw75, HEA319 antigen, CD10, and CD30 turned out to be consistently expressed in different cell types constituting FA and CSP and revealed that in malignant CSP the myoepithelial compartment acquires the ability to invade the stroma. Phenomenologically, the variable mode of expression of CD57 in myoepithelial cells, of CD77 in ductal epithelium, and of CD72 in both epithelial and stromal cells is suggestive for reflecting differences in their functional state but cannot be further interpreted at present. Expression of PR and ER was restricted to duct cells and was relatively independent, non-systematical. However, expression of ER and EGFR was inverse. This was also true for EGFR and CD71 in both duct cells and myoepithelial cells of FA. In contrast, stromal cells of FA were able to co-express EGFR and CD71 in the absence of PR and ER. This suggests a hormone-independent stimulation of the stromal cell compartment, possibly leading to local proliferation as the primary event in tumorigenesis of FA. In malignant CSP, however, the main proliferating cell is an abnormally mobile, HEA319 antigen-, CD10- and CD30-positive myoepithelial cell found to co-express ERFR and CD71 which is abnormal for this cell type but encountered in (myo-)fibroblasts of FA.

Nuclear magnetic resonance for the differentiation of benign and malignant breast tissues and axillary lymph nodes

We have utilized proton T1 (spin-lattice relaxation time) values of Nuclear Magnetic Resonance to study 110 tissue samples obtained from 11 mastectomy specimens. Samples of 1 cm3 from primary tumor sites, nipples, and other breast quadrants, as well as intact lymph nodes were studied and then histologically scored for the presence or absence of carcinoma and, if present, whether it was an isolated microscopic focus (micro). Of 54 samples of breast tissue, 12 contained carcinoma, 5 micro: of 45 lymph nodes, 15 contained metastatic carcinoma, 2 micro; of the 11 nipples, 2 had carcinoma, both micro. For the malignant samples (excluding micro) mean T1 value was 0.47 +/- 0.07 sec, (range 0.39-0.79 sec). For the 72 benign samples (excluding nipple) mean T1 value was 0.26 +/- 0.03 sec (range 0.14-0.36 sec). The 13 tumor-bearing nodes had a mean T1 value of 0.47 +/- 0.03 sec (range 0.40-0.63 sec); mean for the benign nodes was 0.26 +/- 0.007 sec (range 0.19-0.35 sec). The differences were highly significant in each case (p less than 0.001). For micro examples, T1 values were at malignancy threshold levels or just below, except for nipple tissues, where discrimination was poor. For the 20 other malignant samples, there was no correlation between T1 value and the per cent of sample containing malignancy.