Stromal aspects of breast carcinoma

EXPEHIMENTAL

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PATHOLOl:Y

31,

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Stromal

Aspects

of Breast

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Carcinoma

GILLES TREMBLAY Department Royal

of Pathology, Faculty of Victoria Hospital, Mont&al,

hledicine, Qdbec,

hlcGil1 Canada

University H3A 2B4

and

In invasive breast carcinoma, there are wide variations in the ratio of neoplastic cells to stoma and in the relative proportions of the various stromal elements such as connective tissue, elastic tissue, blood vessels and inflammatory cells. The interrelations between these stromal components and the neoplastic cells impart diagnostic features, determine the texture of the mammary tumors and influence their pattern of growth. In the present report some aspects of the stromal reaction are presented; in particular, ultrastructural features of the stroma are correlated with gross traits of breast carcinoma. Electron microscopic study of a series of human scirrhous carcinoma of the breast revealed a stromal population of mesenchymal cells with features of myofibroblasts. These cells displayed prominent rough endoplasnlic reticldum, well-developed Golgi zones, and longitudinal bundles of microfilamcnts with dense bodies. The nuclei frequently had irregular contours with indentations of the nuclear membrane. Part of the cell surface was, at times, covered by a layer of fibrillar material resembling basal lamina. Intercellular junctions were observed between myofibroblasts. It is proposed that myofibroblasts may play a role in the retraction phenomena observed in scirrhous carcinoma such as dimpling of the skin. Elastosis, an increase of elastic tissue, a common occurrence in scirrhous carcinoma. could also contribute to the retraction process.

Histological studies have shown that in invasive breast carcinoma the ratio of neoplastic cells to stroma varies widely. Moreover, the relative proportions of the various stromal elements, including connective tissue, elastic tissue, blood vessels and inflammatory cells also vary considerably. The interrelations between these stromal components and the neoplastic cells contribute diagnostic features, determine the texture of the mammary tumors and influence their growth. 111 the present report some aspects of the stromal reaction will be presented and in particular, ultrastructural features of the stroma will be correlated with gross traits of breast carcinoma. Connective

Tissues

The term “cancer,” which etymologically means “crab,” was used by Hippocrates and all early writers ( Skinner, 1961). In truth, we do not know why these authors selected this name to designate malignant tumors. However, it is believed that probably they wanted to portray the gross appearance of scirrhous breast carcinoma, likening the processes radiating from the edge of the growth to the claws of a crab (Skinner, 1961). Other characteristics of this

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@ 1979 by Academic Press, Inc. of reproduction in any form rexned.

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FIG. 1. Low power electron micrograph of a scirrhous carcinoma showing a myofibroblast ( M) and two tumor cells (T). The myofibroblast contains longitudinal bundles of microfilaments with dense bodies (arrowheads). The nucleus has an irregular contour and displays two nuclear bodies (arrows). x7963.

common form of breast carcinoma are also striking. As the word “scirrhous,” which in Greek means “hard,” implies, the tumor is usualIy very firm. The cut surface is retracted and a grating sound is elicited upon scraping. Histologically, a prominent feature of this type of carcinoma is an abundant fibrous stroma containing varying numbers of fusiform mesenchymal cells.

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In the present work the ultrastructure of the fibrous stroma was studied in 10 human mammary carcinomas of the scirrhous type. It is realized that the term scirrhous carcinoma is rather obsolete and such gross morphology can correspond histologically to either infiltrating lobular or ductal carcinoma (Fisher et al., 1975). Nevertheless, it is employed in this paper to indicate that all tumors studied demonstrated the above described features. On histological examination nine of the tumors were infiltrating ductal carcinoma and one had the pattern of infiltrating lobular carcinoma. For comparison one ductal adenocarcinoma of the pancreas was studied which was hard and retracted below the cut surface. For the electron microscopic study, thin slices were cut from surgical specimens immediately after surgical excision, placed in 3% gluteraldehyde in 0.1 M cacodylate buffer at pH 7.2 and diced. The fragments were postfixed in 1% osmium tetroxide, embedded in Epon-812 and processed for electron microscopy. At the ultrastructural level the stoma of the scirrhous carcinomas showed a population of fibroblasts with an abmldant rough endoplasmic reticulum and prominent, often multiple, Golgi zones. Many of these cells contained bundles of microfilaments which were arranged parallel to the long axis of the cells and often contained scattered dense bodies (Figs. 1-4). Such cells combining ultrastructural characteristics of fibroblasts and smooth muscle cells have been termed myofibroblasts (Gabbiani et nl., 1972). Other features common to myofibroblasts were also present. The nuclei frequently had irregular contours with indentations of the nuclear membrane (Fig. 1). Part of the cell surface was, at times, surrounded by a layer of fibrillar material resembling basal lamina and

FIG. 2. Part of a myofibroblast containing prominent bundles of microfilaments with dense bodies (arrowheads). Three nuclear bodies are seen in the nucleus (arrows). The extracellular material consists of several well formed collagen fibers (C) and an abundance of microfibrils. X 17,253.

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FIG. 3. Detail of a myofibroblast illustrating compact bundles of microfilaments bodies. Well developed rough endoplasmic reticulum and mitochondria occupy cytoplasm. X38,608.

FIG. 4. Fibrillar material resembling basal lamina but remains separated from the cell membrane by a microfilamentous bundle with dense bodies, well and a prominent Golgi zone (G). X25,654.

the

covers part of the cell surface a distinct space. The cytoplasm developed rough endoplasmic

with dense remaining

(arrows) contains reticulum

232

FIG. 5. Details of a myofibroblast the cell surface (arrows). Bundles cytoplasm. X30,300.

GILLES

TREMBLAY

cut transversely; of microfilaments

in

a fibrillary material cross section (F)

covers part of are seen in the

separated from the cell membrane by a clear zone (Figs. 4 and 5). Opposite this extracellular material there was sometimes, immediately beneath the cell membrane, a fibrillar condensation resulting in a structure reminiscent of a hemidesmosome (Fig. 6). Intercellular junctions were also present between myofibroblasts (Fig. 7). Myofibroblastic nuclei often displayed nuclear bodies consisting of fibrils and less commonly, granular material (Figs. 1, 2, and 8). These bodies were either single or multiple. In many instances, two or three, and on occasion, four to six could be identified in a single section of a nucleus. of the ductal adenocarcinoma of the pancreas also displayed numerThe stroma ous myofibroblasts with all the ultrastructural features described above, including prominent multiple nuclear bodies (Fig. 9). The extracellular space contained collagen fibrils and fine fibrils. The relative proportions of the two elements varied, but in some areas the fine fibrils predominated (Fig. 2). The present study reveals that a large proportion of the stromal cells in scirrhous carcinoma are myofibroblasts, a type of cell intermediate between fibrobIasts and smooth muscle cells (Gabbiani et al., 1972; Gabbiani and Montandon, 1977). It is noteworthy that the conditions in which myofibrobIasts have been observed, such as granulation tissue, wound healing, Dupuytren’s contractsme, and Ledderhose’s disease, are characterized by tissue retraction (Gabbiani and Majno, 1972; Ryan et al., 1974; Gabbiani and Montandon, 1977). It has been suggested that in granulation tissue the myofibroblasts, owing to their contractile responsiapparatus and cell-to-cell and cell-to-stroma connections, are probably ble for the overall tissue shrinkage (Ryan et al., 1974). Whether such a me&a-

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FI G. 6. Fibrillar m2 erial on the cell surface (arrow) and zone of cyt oplasmic cond ensaresulting in a hemjde smosome-like comtjon beneath the I )lasn oa membrane (arrowheads) plex. x40,400.

nisnI is involved in the tissue retraction commonly seen in scirl.hous breast carcinaIma remains to ie proved, but the present observations are compatible with this hypothesis. Of interest is the finding that in a pancreatic carcinoma that

FIG..

7. Two intercellnlar

junctions

(arrows)

between

two myofibroblasts.

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FIG. 8. Details of two nuclear bodies consisting of filamentous and granular

material.

x25 ,654.

macroscopically was firm and retracted, the stroma also exhibite Ld a large p(,pulation of myofibroblasts. An intriguing and hitherto unrecorded feature in myofibrc Iblasts was the

FIG. 9. Portion of a myofibroblast in the stroma of a pancreatic adc:nocarcinoma. The nucleus contains five nuclear bodies. Bundles of microfilaments with dense bodies are pn 3ent in the cytoplasm (arrow). x21,600.

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frequent occurrence of prominent nuclear bodies. These organelles have been described in a variety of normal and pathological cells although their function remains unknown. It has been proposed that they are related to cellular hyperactivity (Bouteille et al., 1967; Dupuy-Coin et al., 1972). The extracellular space in the stroma of breast carcinoma contained, in addition to well formed collagen fibers, fibrillar material in varying but often significant amounts. The nature of these fibrils is unknown but a recent finding by Gabbiani et al. (1976) on experimentally induced granulation tissue may be relevant. These investigators reported that chemical analysis of the granulation tissue revealed a high proportion of Type III collagen while a synchronous ultrastructural study demonstrated a large population of myofibroblasts and finely fibrillar material in the extracellular spaces. They concluded that this concurrence suggests that myofibroblasts, in addition to their contractile activity may be involved in the synthesis of Type III collagen and that some of the intercellular fibrillar material might correspond to that type of collagen. In breast carcinoma, as in other types of tumors, it has generally been assumed that collagen fibers in the stroma are the product of host mesenchymal cells. The present finding in the stroma of a population of fibroblasts and myofibroblasts with well-developed rough endoplasmic reticulum and prominent Golgi apparatus is certainly consistent with this interpretation. However, an alternative opinion has been expressed by Al-Adnani et al. (1975) who, using immunohistochemical techniques, reported the presence of collagen and prolylhydroxylase in the neoplastic cells of mammary scirrhous carcinomas. They suggested that the malignant epithelium produces its own stromal collagen and that the scirrhous reaction is not a host response to tumor invasion. Clearly, such a controversial view needs to be further substantiated. There is also a need to establish the type of collagen present in mammary carcinoma and to investigate the interrelation between the neoplastic and stromal cells. However, it seems reasonable to suggest that the myofibroblasts observed in scirrhous carcinoma contribute to the clinical retraction phenomena associated with this neoplasm.

E Zastic Tissue Elastosis, an augmentation of elastic tissue, although described in breast carcinoma years ago, has attracted little attention (Scheel, 1906). However, in recent years new information has been obtained on the nature, incidence, distribution, histogenesis and diagnostic significance of this stromal response. Until recently the only evidence that elastosis consisted of elastic fibers was histochemical, since these fibers stained avidly with elastic stains. Several studies have now established that elastosis corresponds at the ultrastructural level to elastic fibers with the two characteristic components, an amorphous electronlucent core and peripheral microfibrils (Fig. 10) (Schigdt et al., 1972; Tremblay, 1976; Adnet et al., 1976a; Fisher, 1976; Martinez-Hernandez et al., 1977). These fibers also exhibit dense electron opacity when treated with Verhoeff’s iron hematoxylin elastic stain (Fig. 11) (Brissie et al., 1974; Adnet et al., 1976b) . The high incidence of elastosis is well demonstrated by two recent studies in which some degree of elastosis was found in 88.2 and 95% of infiltrating

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mammary carcinomas (Fisher et al., 1975; Adnet et al., 1976a). The change is found in various forms of breast carcinoma but appears to be least frequent in specia1 types, such as medullary and mutinous tumors (Fisher et al., 1975). The increased elastic tissue is disposed mainly around ducts (Lundmark, 1972)) but also occurs in the walls of blood vessels, chiefly veins and diffusely in the stroma ( Azzopardi and Laurini, 1974; Tremblay, 1974). The extent of the lesion varies, but it may be so marked as to be grossly apparent. Indeed, the yelIowish, chalky streaks commonly present on the cut surface of scirrhous carcinoma correspond to periductal elastosis (Jackson and Orr, 1957; Azzopardi and Laurini, 1974); this has been confirmed by ultrastructural examination of dissected streaks (Tremblay, 1976). I n such a situation it would seem possible that the increased elastic tissue contributes to the firmness and contraction phenomena seen in scirrhous carcinoma. In one ultrastructural study of elastosis, no mesenchymal cells were identified in the stroma and it was proposed that tumor cells might be the source of the elastic fibers (Douglas and Shivas, 1974). However, in several other investigations mesenchymal cells with features of active fibroblasts were observed among the elastic fibers and it appears more likely that these ceiIs are responsible for the elastic fiber synthesis (Schigdt et al., 1972; Tremblay, 1976; Fisher, 1976; Adnet et al., 1976a; Martinez-Herandez et al., 1977). The role of the tumor cells remains enigmatic but it has been hypothesized that these cells may have an inducing influence on periductal fibroblasts and vascular smooth muscle cells to over-produce elastic fibers (Azzopardi and Laurini, 1974; Tremblay, 1976).

FIG. 10. Electron micrograph of elastosis in a scirrhous breast carcinoma showing part of a fibroblnst (Fi) and numerous elastic fibers consisting of an amorphous electron-lucent core (A) surrounded by microfibrils (arrow). The fibroblast has an irregular contour \vith deep recesses in which elastic fibers are in close contact with the cell surface ,( arrowheads) (N = NucIeus). X23,113.

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FIG. 11. Elastic fibers s(e) are markedly electron dense when stained with VerhoefI’s iron hematoxylin. A fibroblast (Fi) with irregular contour and cytoplasmic processes is present between the fibers. x8104.

The specificity and the diagnostic significance of elastosis have been the object of diverging views (Orr, 1958; Lundmark, 1972; Sandison, 1962; Davies, 1973). In a recent study elastosis has been demonstrated in a distinctive benign sclerusing lesion of the female breast (Tremblay et al., 1977). This observation does not preclude the possibility that the extensive elastosis so frequently found in breast carcinoma is in some way related to the neoplastic process, but it indicates that other conditions can induce elastic hyperplasia; thus this change should not be utilized as a criterion for malignancy, With regard to the clinical course, Shivas and Douglas (1972) have proposed that assessmentof the degree of elastosis in breast carcinoma can provide a guide to prognosis, large amounts of elastic tissue being associated with longer survival. However, Laurini (1974) in a comparable study concluded that the extent of elastosis is a parameter with limited practical prognostic value. Another issue which needs further investigation is the suggestion that there is a correlation between elastosis and a high level of estrogen receptors in breast cancers ( Masters et nl., 1976). Blood Vessels The growth of infiltrating breast carcinomas, as that of all solid tumors, requires that the stroma provide a continuously expanding network of blood vessels. In this regard one of the most fascinating developments in the last decade has been the demonstration that malignant tumors release a diffusible factor capable of inducing neovascularization in the host (Folkman et al., 1971; Folkman and Cotran, 1976). This Tumor Angiogenesis Factor (TAF) has now been detected in a variety of human and experimental tumors.

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Recent studies by Gimbrone and Gullino (1976a, b; Gullino, 1977) in which the method of mammary neoplasm transplantation on the iris of rabbit eye was used, have revealed that both murine and human carcinomas can elicit a neovascular response. Furthermore, these investigators have obtained some very intriguing results concerning hyperplastic and pre-neoplastic mammary lesions. For instance, in mice, hyperplastic alveolar nodules (HAN), a well characterized pre-neoplastic lesion, were found to induce angiogenesis in 300/O of the cases (Gimbrone and Gullino, 1976a, b). Among human lesions, not only did the 10 invasive carcinomas studied give positive results but also two papillomas, eight of 11 foci of non-invasive carcinoma, seven of 25 hyperplastic lobules, and seven of 36 normal appearing lobules (Brem et al., 1977). In view of these findings and the evidence that carcinogenesis is a multistage process, Gullino (1977) has hypothesized that the acquisition of angiogenic capacity may be an early event and that this phenomenon could be useful in detecting, among hyperplastic and pre-neoplastic breast lesions, those that are at a higher risk of becoming carcinoma. Inflammatory

Cells

Mammary carcinomas, as other malignant tumors, may contain a stromal lymphoid infiltrate of varying intensity. The exact biological significance of this cellular stromal reaction remains uncertain but the long expressed and still prevalent view is that it reflects an immune reaction to the tumor (Ioachim, 1976). As a consequence, many studies have attempted to correlate the inflammatory stromal reaction with the prognosis of tumors. The classical example of lymphoid infiltration in breast cancer is medullary carcinoma, and evidence indicating that this form of tumor has a relatively favorable prognosis was provided in 1949 by Moore and Foote. This observation has been supported by other investigations (Bloom et al., 1970; Maier et al., 1977). In a recent study of 219 cases of medullary carcinoma, Maier et al. (1977) found that the survival rate was 63.7% at 5 years while the overall survival rate for other varieties of breast cancers was 57%. Yet, other studies have failed to corroborate that medullary carcinoma has a favorable prognosis relative to the more common type of invasive breast carcinoma (Flores et al., 1974; Morrison et al., 1973). Morrison et al. (1973) in a comparative survey of the histological appearance and the clinical evaluation of groups of patients with breast carcinoma from Japan, England, and the U.S.A. could not demonstrate a consistent relationship between medullary carcinoma and longer survival. Differences in the morphologic criteria used to define medullary carcinoma might explain, at least in part, these discrepancies. Further data are needed to resolve this question. Conclusion It is natural that for a long time research related to breast carcinoma has concentrated mainly on the neoplastic epithelial cells. However, increasing awareness of the influence of host-tumor relationships on the biological behavior of malignant neoplasms has stimulated interest in the investigation of the stromal reaction in breast cancer. Many studies have now provided pertinent informa-

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tion on several aspects of the interactions between mesenchymal and tumor cells and particularly on some inductive stimuli which appear to emanate from the cancer cells. ACKNOWLEDGMENT The Bernice

author Ottoni

wishes to thank Mr. for careful preparation

Harry ,M. H. Leung of the manuscript.

for

expert

technical

assistance

and

REFERENCES ADNET, J. J., PINTEAUX, A., CAULET, T., HIBON, E., PETIT, J., PLUOT, M., and ROTH, A. (1976a). L’elastose dans les cancers du sein. Etude anatomoclinique, histochimique et ultrastructurale. Ann. Med. Reims 13, 147-153. ADNET, J. J., PINTEAUX, A., POUSSE, G., and CAULET, T. ( 197613). Caracterisation du tissu klastique normal et pathologique en mircoscopie electronique. (Sur coupes semi-fines et coupes fines). Path. Biol. 24, 293-296. AL-ADNANI, M. S., KIRRANE, J. A., and MCGEE, J. O’D. ( 1975). Inappropriate production of collagen and prolyl hydroxylase by human breast cancer cells in zjiuo. Brit. J. Cancer 31, 653-660. AZZOPARDI, J. G., and LAURINI, R. N. (1974). Elastosis in breast cancer. Cancer 33, 17P 183. BLOOM, H. J. G., RICHARDSON, W. W., and FIELDS, J. R. (1970). Host resistance and survival in carcinoma of breast: A study of 194 cases of medullary carcinoma in a series of 1411 cases of breast cancer followed for 20 years. Brit. Med. J. 3, 181-188. BOUTEILLE, M., KALIFAT, S. R., and DELARUE, J. (1967). Ultrastructural variations of nuclear bodies in human disease. .l. Ultrastruct. Res. 19, 474-486. BREM, S. S., JENSEN, H. M., and GULLINO, R. M. (1977). Angiogenesis: A possible marker for neoplastic transformation of human breast parenchyma. Lab. Invest. 36, 331 (abstract). BRISSIE, R. M., SPICER, S. S., HALL, B. J., and THOMPSON, N. T. (1974). Ultrastructural staining of thin sections with iron hematoxylin. J. H&o&em. Cytochem. 22, 895-907. DAVIES, J. D. (1973). Hyperelastosis obliteration and fibrous plaques in major ducts of the human breast. J. Pathol. 110, 13-36. DOUGLAS, J. G., and SHIVAS, A. A. (1974). The origin of elastica in breast carcinoma. .I. R. Coil. Edinb. 19, 89-93. DUPUY-COIN, A. M., KALIFAT, S. R., and BOUTEILLE, M. (1972). Nuclear bodies as proteinaceous structures containing ribonucleoproteins. J. Ultrastruct. Res. 38, 174-187. FISHER, E. ‘R., GREGORIO, R. M., FISHER, B., with assistance of REDMOND, C., VELLIOS, F., SOMMERS, S. C. and cooperating investigators. (1975). The pathology of invasive breast cancer. A syllabus derived from findings of the National Surgical Adjuvant breast project (Protocol 4). Cancer 36, l-85. FISHER, E. R. (1976). Ultrastructure of the human breast and its disorders. Amer. J. Clin. Path. 66, 291-375. FLORES, L., ARLEN, M., ELGUEZABAL, A., LIVINGSTON, S. F., and LEVOWITZ, B. S. (1974). Host tumor relationships in medullary carcinoma of the breast. Surgery 139, 683-688. FOLK~~AN, J., and COTRAN, R. ( 1976). Relation of vascular proliferation to tumor growth. In “Int. Rev. Exp. Path.” (G. W. Richter and M. A. Epstein, eds.), Vol. 16, pp. 207-248. Academic Press, New York/San Francisco/London. Fonxhrm, J., MERLER, E., ABERNATHY, C., and WILLIAMS, G. ( 1971). Isolation of a tumor factor responsible for angiogenesis. .I. Exp. Med. 133, 275-288. GABBIANI, G., HIRSCHEL, B. J., RYAN, G. B., STATKOV, P. R., and MAJNO, G. ( 1972). Granulation tissue as a contractile organ. A study of structure and function. .I. Exp. Med. 135, 719-734. GABBYLNI, G., and MONTANDON, D. (1977). Reparative processes in mammalian wound healing: The role of contractile phenomena. In “International Review of Cytology” (G. H. Boume, J. F. Daniel& and K. W. Jeon, eds.), Vol. 48, pp. 187-219. Academic Press, New YorkPSan FranciscobLondon.

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GABBIAE\‘I, G., and MAJNO, G. (1972). Dupuytren’s contracture: Fibroblast contraction? Amer. J. Path. 66, 131-146. GABBIANI, G., LE Lous, M., BAILEP, A. J., BAZIN, S., and DELAUNAY, A. ( 1976). Collagen A chemical, ultrastructural and immunologic and myofibroblasts of granulation tissue. study. Vi&rows Arch. B. Cell Path. 21, 133-145. GIMBRONE, M. A., and GULLITITO, P. hl. (19’76a). Neovascularization induced by intraocular xenographs of normal, preneoplastic and neoplastic mouse mammary tissues. .I. Nut. Cancer Inst. 56, 305-310. GI~IBRONE, M. A., and GULLISO, P. M. ( 1976b). Angiogenic capacity of preneoplastic lesions of the murine mammary gland as a m:nker of neoplastic transformation. Cancer Res. 36, 2611-2620. GULLKO, P. hl. (1977). Natural history of breast cancer. Progression from hyperplasia to neoplasia as predicted by angiogenesis. Cancer 39, 2697-2703. IOACHI~~, H. L. (1976). The stromal reaction of tumors: An expression of immune surveillance. J. Nat. Cancer Inst. 3, 465-475. JACKSON, J. G., and ORR, J. W. (1957). The ducts of carcinomatous breasts, with particular reference to connective tissue changes. .I. Path. Bact. 74, 265-273. LAIJRINI, R. N. (1974). Prognostic value of elastosis in infiltrative mammary cancer. XI International Cancer Congress, Florence, p, 770. LUNDMARK, C. (1972). Breast cancer and elastosis. Cancer 30, 1195-1201. MAIER, W. P., RosEh~o~D, G. P., GOI,DAIAN, L. I., KAPLAN, G. F., and TYSON, R. R. (1977). A ten year study of medullary carcinoma of the breast. Surg. Gynec. Obstet. 144, 695-698. MARTINEZ-HERNANDEZ, A., FRANCIS, D. J., and SILVERBERG, S. G. (1977). Elastosis and other stromal reactions in benign and malignant breast tissue. An ultrastructural study. Cancer 40, 700-706. MASTERS, J. R. W., SANGSTER, K., HA~KISS, R. A., and SHIVAS, A. A. (1976). Elastosis and oestrogen receptors in human breast cancer. Brit. J. Cancer 33, 342-343. MOORE, 0. S., and FOOTE, F. W. (1949). The relatively favorable prognosis of medullary carcinoma of the breast. Cuncer 2, 635-642. MORRISON, A. S., BLACK, M. M., LOWE, C. It., MACMAHON, B., and YUASA, S (1973). Some international differences in histology and survival in breast cancer. lnt. J. Cancer 11, 261267. ORR, J. W. ( 1958). The significance of connective tissue changes within the ducts in relation to mammary carcinoma. In “International Symposium on Mammary Cancer” (L. Severi, ed.), pp. 209-213. Purugia. RYAN, G. B., CLIFF, W. J., GABBIANI, G., II&, C., MONTAKDON, D., STATGOV, P. R., and MAJXO, G. ( 1974). hfyofibroblasts in human granulation tissue. Human Pith. 5, 55-67. SANDISON, A. T. (1962). An autopsy study of the adult human breast. National Cancer Institute Monograph, No. 8, U.S. Dept. of Health, Education and Welfare, 3-145. SCHEEL, 0. (1906). Uber neubildung des elastichen gewebes in karcinomen, besonders der mamma. Beitr. Path. Anat. 39, 187-198. SCHI@DT, T., JENSEN, H., NIELSEN, M., and RANI&, P. ( 1972). On the nature of amyloidlike duct wall changes in carcinoma of the breast. Acta Path. Microbial, Scud [A] 80, Suppl. 233, 151-157. SHIVAS, A. A., and DOUGLAS, J. G. ( 1972). The prognostic significance of elastosis in breast carcinoma. J. R. Coil. Surg. E&b. 17, 315-320. SKINNER, H. A. ( 1961). “The Origin of Medical Terms.” The Williams and Wilkins Company, Baltimore, Md., p. 88. TnEMnLAY, G. ( 1974). Elastosis in tubular carcinoma of the breast. Arch. Path. 98, 302307. TmMnLAY, G. ( 1976). Ultrastructure of elastosis in scirrhous carcinoma of the breast. Cancer 37, 307-316. TmMnLAY, G., B=.L, R. H., SEEMAYER, T. A. (1977). Elastosis in benign sclerosing ducta proliferation of the female breast. Amer. J. Surg. Path. f, 155-159.