INTRODUCTION<\/p>\n
Andrew H. Fischer, M.D<\/em><\/p>\n Note: The cell block images presented here were generated using a manual method during development of the automated instrument.<\/p>\n FNA of the breast is an effective means of identifying breast cancers to allow definitive treatment, while accurately excluding malignancy in most benign lesions. [1, 2]<\/sup> Compared to core biopsy, there is decreased morbidity, including hematoma, infection, pain, and risk of seeding of the biopsy track. Nevertheless, the past decade has seen a decline in breast FNA in favor of more aggressive core biopsy techniques. Some pathologists prefer the histologic evaluation of core biopsies because they can be analyzed relatively quickly and easily, and they allow immunohistochemistry (IHC) to be applied. Cell blocks of breast FNA’s offer these same advantages. Combining FNA with core biopsies has been shown to increase diagnostic accuracy. [3]<\/sup> Our recent experience suggests that combining a cytology preparation of a breast FNA with a cell block can also combine the advantages of both approaches. [4]<\/sup><\/p>\n Current cytologic classification of breast cytology samples [5]<\/sup> includes 5 categories: Negative for malignant cells (which can encompass mild proliferative changes), Atypical, Suspicious, Malignant and Unsatisfactory for diagnosis. The atypical category is a major dilemma for breast FNA. Criteria for atypical lesions have shown poor reproducibility, and atypical breast FNA’s are found on follow-up to correspond to cancer in 1\/3 to half of the cases. [2, 3, 6]<\/sup> Because of the high rate of cancer following an “atypical” breast FNA result, biopsy is generally recommended. [5]<\/sup> The suspicious category is also problematic. The surgeon’s decision to perform cancer surgery at the outset (mastectomy or lumpectomy with attempt to achieve adequate resection margins, together with lymph node sampling) is important to avoid multiple costly surgeries that can lead to sub-optimal cosmetic results. To avoid over treatment of benign lesions and achieve optimal cosmetic results, surgeons may need to perform a second diagnostic biopsy following a suspicious cytology FNA diagnosis.<\/p>\n The major problem in classifying proliferative ductal lesions by cytology is that tissue-level changes define the degree of hyperplasia rather than cytologic changes. [7]<\/sup> Hyperplasia is defined as the stratification of ductal cells away from the basement membrane microenvironment. The degree of hyperplasia is graded histologically into usual ductal hyperplasia and atypical ductal hyperplasia.<\/p>\n The major problem in classifying proliferative ductal lesions by cytology is that tissue-level changes define the degree of hyperplasia rather than cytologic changes. [7]<\/sup> Hyperplasia is defined as the stratification of ductal cells away from the basement membrane microenvironment. The degree of hyperplasia is graded histologically into usual ductal hyperplasia and atypical ductal hyperplasia.<\/p>\n In usual ductal hyperplasia, polarity between adjacent cells is often focally maintained with alignment of the long axis of cells in the same direction. This alignment gives a streaming, or vague “school of fish”, appearance to the stratified population. The long axis of the cells in usual hyperplasia also tends to align itself with any residual lumina within the duct, and the residual lumina tend to have an elongated shape with a fuzzy edge. Nuclear spacing in usual hyperplasia tends to vary over the diameter of the duct. Usual hyperplasia often shows an admixture of a distinctly different myoepithelial cell population admixed with the ductal cells. Note that pagetoid extension of mammary carcinoma in benign ducts can simulate an admixture of cell types. [7]<\/sup> Finally, in usual hyperplasia, the overall appearance of the cells may vary predictably depending on how far the cells have stratified away from the basement membrane. Commonly, the nucleus becomes darker and cytoplasm becomes denser as the cells stratify further from the native basement membrane zone.[8]<\/sup><\/p>\n Atypical ductal hyperplasia is characterized by a stratifying population with loss of shared polarity (no streaming) between adjacent cells, no apparent admixed myoepithelial cells, residual lumina that become more smoothly rounded (“punched out”) with the long axis of the nuclei randomized with respect to the edges of the lumina, and no apparent maturation of the cells as they stratify further from the basement membrane zone. [8]<\/sup> In most cases, these features are easy to note at low magnification in histologic sections. Ductal carcinoma in situ is diagnosed when the above features of atypical hyperplasia are unequivocally developed and the population of cells extends over many ducts.<\/p>\n Many of these diagnostic histologic features that distinguish the degree of hyperplasia are difficult or impossible to discern in cytology preparations unless high magnification is used to focus up and down through piles of cells. On the other hand, there are some features that cytologists can use to characterize and recognize ductal proliferations that surgical pathologists cannot use. Discohesion of the ductal cells is one important feature. Cell blocks capture individual discohesive cells to allow this important feature to be noted.<\/p>\n It is important to note that nuclear atypia is not characteristic of low grade ductal carcinoma in situ or atypical hyperplasia. Nuclear atypia is a feature of high grade ductal carcinomas. Cell blocks preserve nuclear features crisply, comparable to cytology preparations, allowing both the low grade architectural changes and the high grade cytologic changes to be detected.<\/p>\n A difficult differential diagnosis in breast FNA is the distinction between fibroadenoma, papilloma and papillary carcinoma. The distinction is important because fibroadenomas, if confidently diagnosed, do not have to be excised. Central papillomas do not necessarily need to be excised, or require only gross excision. On the other hand, papillary carcinomas require careful complete excision with clear margins. The distinction between papilloma and papillary carcinoma is defined by the absence of a myoepithelial cell population in the latter, or the presence of stratification that meets architectural criteria for in-situ carcinoma. Myoepithelial cells can be difficult or impossible to discern in monolayer cytology preparations and papillomas can show considerable stratification and nuclear atypia. Thus the distinction of papillary carcinoma and papilloma is widely considered to be nearly impossible on cytology preparations alone. While some residual myoepithelial cells are often retained next to the basement membrane in ductal carcinoma in situ, a non-invasive papillary carcinoma infrequently shows residual myoepithelial cells. [7]<\/sup> Immunohistochemical staining for myoepithelial cells (calponin, p63, and smooth muscle actin) in cell block sections can be very useful to distinguish papillomas from papillary carcinomas. [9, 10, 11, 12]<\/sup><\/p>\n Distinction of lobular from ductal carcinoma is difficult by cytopathology. The distinction can occasionally be important. Since lobular carcinoma in situ is sometimes not treated surgically, the rare occurrence of lobular carcinoma in situ as an incidental finding (e.g., colonizing a fibroadenoma) could lead to excessive surgery. On FNA cytology preparations, lobular carcinomas are generally very sparsely cellular and are easily under-diagnosed. Not only are there generally few cells, the cells can be very bland. Lack of polarity in the sparse cells, and the presence of “targetoid” mucin vacuoles is a helpful diagnostic trait of lobular carcinoma. Intracellular mucin is very rare in normal ductal cells, and its presence can be demonstrated in cell blocks. Lobular carcinoma is characterized by loss of E-Cadherin expression which can be detected in histologic sections by immunohistochemistry [12]<\/sup>. We have noted that the stromal tissue fragments obtained by FNA often have entrapped lobular carcinoma cells that can be seen in cell blocks, suggesting that the addition of a cell block to breast FNA can help improve the detection and specific diagnosis of lobular carcinoma.<\/p>\n Cytology preparations do not allow the presence of invasion to be diagnosed. [13]<\/sup> Since in situ cancers may not need lymph node sampling, this has been an important limitation of breast FNA for planning treatment. Through the use of cell blocks, we recently found that invasion can be diagnosed in a significant proportion of breast cancer FNA’s. [4]<\/sup><\/p>\n In this chapter, we will show that combining cytology preparations with cell blocks allows the best of both worlds: micro-sized biopsies obtained by FNA allow cytologic as well as histologic criteria to be applied.<\/p>\n Benign<\/p>\n Benign ductal cells, Breast FNA, ThinPrep\u00ae<\/sup>.<\/strong> Benign ductal cells, Breast FNA, ThinPrep\u00ae<\/sup>.<\/strong> Benign ductal cells, Breast FNA, Cell Block.<\/strong> Benign ductal cells, Breast FNA, Cell Block.<\/strong> Usual Ductal Hyperplasia<\/p>\n Proliferative ductal lesion, Breast FNA, Direct smear.<\/strong> Proliferative ductal lesion, Breast FNA, Direct smear.<\/strong> Usual ductal hyperplasia, Breast FNA, Cell Block.<\/strong> Usual ductal hyperplasia, Breast FNA, Cell Block.<\/strong> Usual ductal hyperplasia, Breast FNA, Cell Block.<\/strong> Usual ductal hyperplasia, Breast FNA, Cell Block.<\/strong> Atypical Ductal Hyperplasia<\/p>\n Atypical ductal proliferative lesion, Breast FNA, Diff-Quick stained smear.<\/strong> Atypical ductal proliferative lesion, Breast FNA, ThinPrep\u00ae<\/sup>.<\/strong> Atypical ductal proliferative lesion, Breast FNA, ThinPrep\u00ae<\/sup>.<\/strong> Usual ductal hyperplasia, Breast FNA, Cell Block.<\/strong> Suspicious ductal proliferative lesion, Breast FNA, ThinPrep\u00ae<\/sup>.<\/strong> Atypical ductal hyperplasia, Breast FNA, Cell Block.<\/strong> Atypical ductal hyperplasia, Breast FNA, Cell Block.<\/strong> Ductal proliferative lesion, Papillary neoplasm vs. fibroadenoma, Breast FNA, Direct smear.<\/strong>
\nfor an enlarged view.<\/strong><\/p>\n
\n![\"Image](\"\/gallery\/images_large\/slide1601.jpg\" "\\"Click")
<\/a><\/p>\n
\nNormal ductal cells form a single cell layer attached to a basement membrane. The 2-dimensionally arranged ductal cells are cohesive with each other but strip away with ease from the basement membrane in fine needle aspirates. When seen in a monolayer preparation, the ductal cells typically lie as a flat sheet parallel to the slide surface (right). They can also remain as an intact single cell thick duct (lower portion). Smaller ductules (upper left) can show more complex shapes and it may be more difficult to appreciate that the cells are still only one cell layer thick without focusing up and down.20X<\/div>\n<\/div>\n
\n<\/strong>
\nBenign ductal cells, Breast FNA, ThinPrep\u00ae<\/sup>.<\/strong>
\nNormal ductal cells form a single cell layer attached to a basement membrane. The 2-dimensionally arranged ductal cells are cohesive with each other but strip away with ease from the basement membrane in fine needle aspirates. When seen in a monolayer preparation, the ductal cells typically lie as a flat sheet parallel to the slide surface (right). They can also remain as an intact single cell thick duct (lower portion). Smaller ductules (upper left) can show more complex shapes and it may be more difficult to appreciate that the cells are still only one cell layer thick without focusing up and down.20X<\/div>\n<\/a><\/p>\n
\nMyoepithelial cells are another cell type that normally lie between the basement membrane and the ductal cells. They typically have slightly darker nuclei, and paler fragile cytoplasm that may rupture when the ductal cells strip from the basement membrane.
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\n<\/strong>
\nBenign ductal cells, Breast FNA, ThinPrep\u00ae<\/sup>.<\/strong>
\nMyoepithelial cells are another cell type that normally lie between the basement membrane and the ductal cells. They typically have slightly darker nuclei, and paler fragile cytoplasm that may rupture when the ductal cells strip from the basement membrane.
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\n<\/a><\/p>\n
\n<\/strong>
\nBenign ductal cells, Breast FNA, ThinPrep\u00ae<\/sup>.
\nBy focusing up and down, one can see that the myoepithelial cells of a normal duct lie loosely but predictably in a plane parallel to the ductal cells.
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\n<\/strong>
\nBenign ductal cells, Breast FNA, ThinPrep\u00ae<\/sup>.<\/strong>
\nBy focusing up and down, one can see that the myoepithelial cells of a normal duct lie loosely but predictably in a plane parallel to the ductal cells.
\n40X<\/div>\n
\n<\/a><\/p>\n
\nWhat appeared as a flat sheet on ThinPrep\u00ae<\/sup> appears as a line of cells. It is easy to see at low magnification that benign ductal cells are only one cell in thickness. Note the loosely adherent myoepithelial cells around the outside of the duct.
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\n<\/strong>
\nBenign ductal cells, Breast FNA, Cell Block.<\/strong>
\nWhat appeared as a flat sheet on ThinPrep\u00ae<\/sup> appears as a line of cells. It is easy to see at low magnification that benign ductal cells are only one cell in thickness. Note the loosely adherent myoepithelial cells around the outside of the duct.
\n20X<\/div>\n
\n<\/a><\/p>\n
\nOne can tell that the cells are not truly piled up away from the basement membrane-myoepithelial zone by noting that the cytoplasm becomes predictably more abundant at the edge of the tangential area (arrow).
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\n<\/strong>
\nBenign ductal cells, Breast FNA, Cell Block.<\/strong>
\nOne can tell that the cells are not truly piled up away from the basement membrane-myoepithelial zone by noting that the cytoplasm becomes predictably more abundant at the edge of the tangential area (arrow).
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\n<\/a><\/p>\n
\nStratification of the ductal cells is known as hyperplasia or proliferative change. Obscuring blood and the thickness of the fragments make it difficult to gauge how much hyperplasia is present.
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\n<\/strong>
\nProliferative ductal lesion, Breast FNA, Direct smear.<\/strong>
\nStratification of the ductal cells is known as hyperplasia or proliferative change. Obscuring blood and the thickness of the fragments make it difficult to gauge how much hyperplasia is present.
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\n<\/a><\/p>\n
\nAt higher magnification, by focusing up and down, one can appreciate some probable myoepithelial cells admixed with the ductal cells, and probable slit-like spaces. These two features are characteristic of usual-type ductal hyperplasia, a lesion that conveys a roughly two fold increased relative risk of subsequent breast cancer [14].
\n40X<\/div>\n<\/div>\n
\n<\/strong>
\nProliferative ductal lesion, Breast FNA, Direct smear.<\/strong>
\nAt higher magnification, by focusing up and down, one can appreciate some probable myoepithelial cells admixed with the ductal cells, and probable slit-like spaces. These two features are characteristic of usual-type ductal hyperplasia, a lesion that conveys a roughly two fold increased relative risk of subsequent breast cancer [14]<\/sup>.
\n40X<\/div>\n
\n<\/a><\/p>\n
\nThis needle rinse from the case in Figure 5 shows benign ductal cells as single-cell thick strips of epithelium on the right half of the image. On the left is an area of usual hyperplasia. The stratification of the cells in this area cannot be explained by tangential sectioning. From this low magnification, one can see slit-like spaces interrupting the stratifying ductal cells. Also characteristic of usual ductal hyperplasia is the presence of an admixture of cells with differing cytologic features (myoepithelial cells) in the stratifying population.
\n10X<\/div>\n<\/div>\n
\n<\/strong>
\nUsual ductal hyperplasia, Breast FNA, Cell Block.<\/strong>
\nThis needle rinse from the case in Figure 5 shows benign ductal cells as single-cell thick strips of epithelium on the right half of the image. On the left is an area of usual hyperplasia. The stratification of the cells in this area cannot be explained by tangential sectioning. From this low magnification, one can see slit-like spaces interrupting the stratifying ductal cells. Also characteristic of usual ductal hyperplasia is the presence of an admixture of cells with differing cytologic features (myoepithelial cells) in the stratifying population.
\n10X<\/div>\n
\n<\/a><\/p>\n
\nNote the admixture of darker and lighter-staining nuclei, and the elongated spaces. In usual ductal hyperplasia, the cells tend to align along the axis of the spaces (arrows). Another useful diagnostic trait is the alignment of the long axis of the nuclei of adjacent cells, with a streaming or vague “school of fish” pattern (open arrow). These features, evident at relatively low magnification in histologic sections, can be difficult or impossible to appreciate in cytology preparations.
\n40X<\/div>\n<\/div>\n
\n<\/strong>
\nUsual ductal hyperplasia, Breast FNA, Cell Block.<\/strong>
\nNote the admixture of darker and lighter-staining nuclei, and the elongated spaces. In usual ductal hyperplasia, the cells tend to align along the axis of the spaces (arrows). Another useful diagnostic trait is the alignment of the long axis of the nuclei of adjacent cells, with a streaming or vague “school of fish” pattern (open arrow). These features, evident at relatively low magnification in histologic sections, can be difficult or impossible to appreciate in cytology preparations.
\n40X<\/div>\n
\n<\/a><\/p>\n
\nBenign ductal cells above with mild columnar change contrast with the area of usual ductal hyperplasia below. Note the admixture of distinctly different cell types in the center, some with large pale nuclei and others with small dark nuclei.
\n40X<\/div>\n<\/div>\n
\n<\/strong>
\nUsual ductal hyperplasia, Breast FNA, Cell Block.<\/strong>
\nBenign ductal cells above with mild columnar change contrast with the area of usual ductal hyperplasia below. Note the admixture of distinctly different cell types in the center, some with large pale nuclei and others with small dark nuclei.
\n40X<\/div>\n
\n<\/a><\/p>\n
\nNote the streaming of nuclei in the area to the left, reminiscent of a “school of fish” (arrow).
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\n<\/strong>
\nUsual ductal hyperplasia, Breast FNA, Cell Block.<\/strong>
\nNote the streaming of nuclei in the area to the left, reminiscent of a “school of fish” (arrow).
\n40X<\/div>\n<\/a><\/div>\n
\nDuctal cells are piled up in three dimensions. There is no distinct admixed population of myoepithelial cells, and there is only focal possible shared polarity of adjacent ductal cells in the lower left.
\n60X<\/div>\n<\/div>\n
\n<\/strong>
\nAtypical ductal proliferative lesion, Breast FNA, Diff-Quick stained smear.<\/strong>
\nDuctal cells are piled up in three dimensions. There is no distinct admixed population of myoepithelial cells, and there is only focal possible shared polarity of adjacent ductal cells in the lower left.
\n60X<\/div>\n<\/a><\/div>\n
\nNote the marked stratification of cells. A vague streaming pattern is evident in the center favoring a benign ductal hyperplasia, but without being able to characterize the architectural arrangement of the cells, it is not possible to definitively exclude atypical ductal hyperplasia.
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\n<\/strong>
\nAtypical ductal proliferative lesion, Breast FNA, ThinPrep\u00ae<\/sup>.<\/strong>
\nNote the marked stratification of cells. A vague streaming pattern is evident in the center favoring a benign ductal hyperplasia, but without being able to characterize the architectural arrangement of the cells, it is not possible to definitively exclude atypical ductal hyperplasia.
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\n<\/a><\/p>\n
\nAtypical features include the slightly discohesive ductal population (note the individual ductal cells), the presence of a stratifying population of ductal cells without an obvious admixture of myoepithelial cells, and the near absence of a shared polarity among the ductal cells.
\n60X<\/div>\n<\/div>\n
\n<\/strong>
\nAtypical ductal proliferative lesion, Breast FNA, ThinPrep\u00ae<\/sup>.<\/strong>
\nAtypical features include the slightly discohesive ductal population (note the individual ductal cells), the presence of a stratifying population of ductal cells without an obvious admixture of myoepithelial cells, and the near absence of a shared polarity among the ductal cells.
\n60X<\/div>\n
\n<\/a><\/p>\n
\nNote how the cytoplasmic features change predictably toward the lower right of the field. This feature of usual hyperplasia is difficult to appreciate in cytology preparations. There is also some alignment of the long axis of the ductal cell nuclei with a subtle but distinctive benign streaming pattern, especially toward the lower right. Note also the alignment of ductal cell nuclei parallel with the elongated spaces.
\n40X<\/div>\n<\/div>\n
\n<\/strong>
\nUsual ductal hyperplasia, Breast FNA, Cell Block.<\/strong>
\nNote how the cytoplasmic features change predictably toward the lower right of the field. This feature of usual hyperplasia is difficult to appreciate in cytology preparations. There is also some alignment of the long axis of the ductal cell nuclei with a subtle but distinctive benign streaming pattern, especially toward the lower right. Note also the alignment of ductal cell nuclei parallel with the elongated spaces.
\n40X<\/div>\n
\n<\/a><\/p>\n
\nExcept for some possible shared polarity in the ductal cell group just left of center, the findings are worrisome due to the presence of a monomorphic population of cells that stratify and show discohesion.
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\n<\/strong>
\nSuspicious ductal proliferative lesion, Breast FNA, ThinPrep\u00ae<\/sup>.<\/strong>
\nExcept for some possible shared polarity in the ductal cell group just left of center, the findings are worrisome due to the presence of a monomorphic population of cells that stratify and show discohesion.
\n40X<\/div>\n
\n<\/a><\/p>\n
\nThis image from the needle rinse of the case in Figure 15 shows a uniform population of freely stratifying ductal cells with uniform spacing of nuclei, absence of a streaming pattern, and the presence of more uniformly rounded spaces in the smaller fragment.
\n10X<\/div>\n<\/div>\n
\n<\/strong>
\nAtypical ductal hyperplasia, Breast FNA, Cell Block.<\/strong>
\nThis image from the needle rinse of the case in Figure 15 shows a uniform population of freely stratifying ductal cells with uniform spacing of nuclei, absence of a streaming pattern, and the presence of more uniformly rounded spaces in the smaller fragment.
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\n<\/a><\/p>\n
\nNote the uniformity of the cells (indicating an absence of myoepithelial cells), and the uniform spacing of cells without shared polarity.
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\n<\/strong>
\nAtypical ductal hyperplasia, Breast FNA, Cell Block.<\/strong>
\nNote the uniformity of the cells (indicating an absence of myoepithelial cells), and the uniform spacing of cells without shared polarity.
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\n<\/a><\/p>\n
\nBlood partially obscures cellular detail, but a large cluster of proliferative ductal cells can be seen on the left. A stromal fragment with rounded edges is seen on the right.
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\n<\/strong>
\nDuctal proliferative lesion, Papillary neoplasm vs. fibroadenoma, Breast FNA, Direct smear.<\/strong>
\nBlood partially obscures cellular detail, but a large cluster of proliferative ductal cells can be seen on the left. A stromal fragment with rounded edges is seen on the right.
\n10X<\/div>\n