Difference between revisions of "Breast cytopathology"

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'''[[Breast]] cytopathology''' is a relatively small part of cytopathology, as core biopsies are more in style.
'''[[Breast]] cytopathology''', also '''breast cytology''', is a relatively small part of cytopathology, as core biopsies are more in style.


This article deals only with breast cytopathology.  An introduction to cytopathology is in the ''[[cytopathology]]'' article.
This article deals only with breast cytopathology.  An introduction to cytopathology is in the ''[[cytopathology]]'' article.


==Overview==
=Overview=
===Common indications===
===Common indications===
#FNA done for a clinically benign lesion - unusual to find malignancy.
#FNA done for a clinically benign lesion - unusual to find malignancy.
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*If there are stripped bipolar nuclei (these represent normal stromal cell) - cannot call overt malignancy.<ref>SB. 27 January 2010.</ref>
*If there are stripped bipolar nuclei (these represent normal stromal cell) - cannot call overt malignancy.<ref>SB. 27 January 2010.</ref>


==Normal==
=Normal breast=
Features:
Features:
*Sheets of flat cells.
*Sheets of flat cells.
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*Adipose tissue may represent a [[lipoma]].
*Adipose tissue may represent a [[lipoma]].


==Breast cytopathology in a table==
=Breast cytopathology in a table=
The common entities in breast cytopathology and their features:
The common entities in breast cytopathology and their features:
{| class="wikitable"
{| class="wikitable"
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| Flat sheets & fluffy paucicellular (fibrous) tissue
| Flat sheets & fluffy paucicellular (fibrous) tissue
| '''Mixed pop. in cluster'''; nuclei: oval/spindle (myoepi.) and round (epi.).
| '''Mixed pop. in cluster'''; nuclei: oval/spindle (myoepi.) and round (epi.).
| [http://commons.wikimedia.org/wiki/File:Breast_fibroadenoma_by_fine_needle_aspiration_%282%29_PAP_stain.jpg Fibroadenoma - FNA (WC)], [http://commons.wikimedia.org/wiki/File:Breast_fibroadenoma_by_fine_needle_aspiration_%281%29_DG_stain.jpg Fibroadenoma FNA - Diff-Quik (WC)], [http://www.flickr.com/photos/jian-hua_qiao_md/3975095095/ Fibroadenoma (flickr.com)]
| [[Image:Breast_fibroadenoma_by_fine_needle_aspiration_%282%29_PAP_stain.jpg | thumb | 150px | center | Fibroadenoma - FNA (WC)]]
|-
|-
| Fibrocystic change
| Fibrocystic change
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| May have flat sheets of cells
| May have flat sheets of cells
| Oncocytic change (apocrine change) common, histocytes (foamy cytoplasm), [[nucleoli]], large NCR
| Oncocytic change (apocrine change) common, histocytes (foamy cytoplasm), [[nucleoli]], large NCR
| [http://commons.wikimedia.org/wiki/File:Fibrocystic_changes_of_breast_-_cytology_1.jpg Oncocytes in FCC (WC)]
| [[Image:Fibrocystic_changes_of_breast_-_cytology_1.jpg |thumb|150px | center | Oncocytes in FCC. (WC)]]
|-
|-
| Papillary neoplasm
| Papillary neoplasm
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| Sheets, usu. flat?
| Sheets, usu. flat?
| Variable size, nucleolus
| Variable size, nucleolus
| [http://commons.wikimedia.org/wiki/File:Breast_papillary_neoplasm_1.jpg Papillary neoplasm (WC)]
| [[Image:Breast_papillary_neoplasm_1.jpg|thumb|150px| center | Papillary neoplasm. (WC)]]
|-
|-
| Ductal carcinoma
| Ductal carcinoma
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| '''3-D clusters'''
| '''3-D clusters'''
| Nuclear size variation, '''membrane irreg.''', nucleoli (prominent) - every cell, cell size var.
| Nuclear size variation, '''membrane irreg.''', nucleoli (prominent) - every cell, cell size var.
| [http://commons.wikimedia.org/wiki/File:Ductal_carcinoma_-_cytology.gif Ductal carcinoma - animation showing 3-D nature (WC)]
| [[Image:Ductal_carcinoma_2_-_cytology.jpg |thumb|150px |center | Ductal carcinoma. (WC)]]
|}
|}


==Fat [[necrosis]]==
=Diagnoses=
==Fat necrosis of the breast==
===General===
Etiology - various:<ref name=pmid19234281/>
*Trauma.
*Surgery.
*Radiation.


===Microscopic===
===Cytology===
Features:<ref name=pmid19234281>{{Cite journal  | last1 = Taboada | first1 = JL. | last2 = Stephens | first2 = TW. | last3 = Krishnamurthy | first3 = S. | last4 = Brandt | first4 = KR. | last5 = Whitman | first5 = GJ. | title = The many faces of fat necrosis in the breast. | journal = AJR Am J Roentgenol | volume = 192 | issue = 3 | pages = 815-25 | month = Mar | year = 2009 | doi = 10.2214/AJR.08.1250 | PMID = 19234281 | URL = http://www.ajronline.org/content/192/3/815.full }}</ref>
Features:<ref name=pmid19234281>{{Cite journal  | last1 = Taboada | first1 = JL. | last2 = Stephens | first2 = TW. | last3 = Krishnamurthy | first3 = S. | last4 = Brandt | first4 = KR. | last5 = Whitman | first5 = GJ. | title = The many faces of fat necrosis in the breast. | journal = AJR Am J Roentgenol | volume = 192 | issue = 3 | pages = 815-25 | month = Mar | year = 2009 | doi = 10.2214/AJR.08.1250 | PMID = 19234281 | URL = http://www.ajronline.org/content/192/3/815.full }}</ref>
*Dying/dead adipocytes:
*Dying/dead adipocytes:
**Light pink "low density" whispy poorly demarcated blobs - lack a nucleus.
**Light pink "low density" whispy poorly demarcated blobs - lack a nucleus.
***Early: cellular outlines seen, light pink - loose.
**#Early: cellular outlines seen, light pink/loose cytoplasm.
***Mid: adipocytes collapsed/more dense.
**#Mid: cellular outlines indistinct, dense pink cytoplasm.
****Foamy macrophages - adjacent to fat.
**#*Foamy macrophages - adjacent to fat.
*****Abundant cytoplasm - with granular (pink) crap inside.
**#**Abundant cytoplasm with granular (pink) crap inside.
*****Oval nucleus with small nucleolus.
**#**Oval nucleus with small nucleolus.
***Late:
**#Late:
****Macrophages: multinucleated giant-cells.
**#*Macrophages: multinucleated giant-cells.
****Calcification.
**#*Calcification.
*+/-[[Myospherulosis]] - granulomatous reaction of fat & blood.
**Round aggregate of [[RBC]]s ~10-20 RBCs in diameter.


Notes:
Notes:
*Healthy adipocytes - large cells, clear cytoplasm.
*Healthy adipocytes - large cells, clear cytoplasm.
*Myospherulosis - due to exposure to fat, may be seen in the context of malignancy.<ref name=pmid11035579>{{Cite journal  | last1 = Chau | first1 = KY. | last2 = Pretorius | first2 = JM. | last3 = Stewart | first3 = AW. | title = Myospherulosis in renal cell carcinoma. | journal = Arch Pathol Lab Med | volume = 124 | issue = 10 | pages = 1476-9 | month = Oct | year = 2000 | doi = 10.1043/0003-9985(2000)1241476:MIRCC2.0.CO;2 | PMID = 11035579 }}</ref>


Images:
====Images====
*[http://www.ajronline.org/content/192/3/815/F1.expansion.html Early fat necrosis (ajronline.org)].
*[http://www.ajronline.org/content/192/3/815/F1.expansion.html Early fat necrosis (ajronline.org)].
*[http://www.ajronline.org/content/192/3/815/F4.expansion.html Mid fat necrosis (ajronline.org)].
*[http://www.ajronline.org/content/192/3/815/F4.expansion.html Mid fat necrosis (ajronline.org)].
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*[http://www.ajronline.org/content/192/3/815/F6.expansion.html Late fat necrosis - calcifications (ajronline.org)].
*[http://www.ajronline.org/content/192/3/815/F6.expansion.html Late fat necrosis - calcifications (ajronline.org)].


==Adenocarcinoma==
==Ductal carcinoma==
*By convention one usually calls everything ''ductal carcinoma''.
*By convention one usually calls everything ''ductal carcinoma''.  It is the same as ''mammary carcinoma''.


===Cytopathology===
===Cytology===
Five features:<ref>Foundations Series - FNA book.</ref>
Features:
#Cellular size variation.
*Classic five:<ref>{{Ref FNAC|137}}</ref>
#Nuclear size variation.
*#Cellular size variation.
#*May be marked adjacent cells different by factor of 2.
*#Nuclear size variation.
#*Typically ''not'' marked - often ~1.5.
*#*May be marked adjacent cells different by factor of 2.
#Nucleoli.
*#*Typically ''not'' marked - often ~1.5.
#*Should be in every cell.
*#Nucleoli.
#*Multiple suggestive of malignant.
*#*Should be in every cell.
#Irregular chromatin pattern.
*#*Multiple suggestive of malignant.
#Lack of singular bipolar nuclei (in the background), '''key negative'''.
*#Irregular chromatin pattern.
Other features:
*#Lack of singular bipolar nuclei (in the background), '''key negative'''.
*3-D clusters - strong indicator.
*Other features:
*Cytoplasmic vacuoles - considered a classic finding.
**3-D clusters - strong indicator.
**Cytoplasmic vacuoles - considered a classic finding.


Notes:
Notes:
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**Exceptions are ''tubular carcinoma'' and ''colloid carcinoma''; these have cells found in clusters or tubules/glands.<ref name=Ref_APBR678>{{Ref APBR|678}}</ref>
**Exceptions are ''tubular carcinoma'' and ''colloid carcinoma''; these have cells found in clusters or tubules/glands.<ref name=Ref_APBR678>{{Ref APBR|678}}</ref>
*Intracytoplasmic "lumens"/inclusions (think ''lobular carcinoma'').
*Intracytoplasmic "lumens"/inclusions (think ''lobular carcinoma'').
*A useful rule of thumb: strongly suggestive of malignant ~3x RBC diameter & dyscohesive.<ref>Chan, S. 26 April 2012.</ref>
DDx:
*[[Breast cytopathology#Fibroadenoma|Fibroadenoma]].
====Images====
<gallery>
Image:Ductal_carcinoma_-_cytology.gif | Ductal carcinoma - animation showing 3-D nature. (WC)
Image:Ductal_carcinoma_2_-_cytology.jpg | Ductal carcinoma. (WC)
</gallery>
==Lobular carcinoma==
{{Main|Invasive lobular carcinoma}}
===Cytology===
Features:
*Discohesive, small, plasmacytoid cells.
*Targetoid mucin - '''key features'''.
==Tubular carcinoma==
{{Main|Tubular carcinoma of the breast}}
===Cytology===
Features:
*Tubular structure with sharp point - '''key feature'''.
==Mucinous carcinoma==
{{Main|Mucinous carcinoma of the breast}}
===Cytology===
Features:
*Mucin - blue/gray acellular material.
*Nuclear atypia.


Images:
DDx:
*[http://commons.wikimedia.org/wiki/File:Ductal_carcinoma_-_cytology.gif Ductal carcinoma - animation showing 3-D nature (WC)].
*Mucocele.
*[http://commons.wikimedia.org/wiki/File:Ductal_carcinoma_2_-_cytology.jpg Ductal carcinoma (WC)].


==Fibroadenoma==
==Fibroadenoma==
{{Main|Fibroadenoma}}
===General===
*Pitfall #1 for a malignant diagnosis, i.e. ''ductal carcinoma''.
===Cytology===
Features:<ref name=Ref_APBR676>{{Ref APBR|676}}</ref>
Features:<ref name=Ref_APBR676>{{Ref APBR|676}}</ref>
*Flat sheet of cells with '''mixed population - key feature''':
*Flat sheets of cells with finger-link projections (called "antler horns") with a mixed cell population:
**Cells with round nuclei (epithelium).
**Cells with round nuclei (epithelium).
**Cells with oval nuclei (myoepithelium).
**Cells with oval nuclei (myoepithelium).
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**Spindle cells.
**Spindle cells.
**Fluffy appearance - relatively paucicellular.
**Fluffy appearance - relatively paucicellular.
*Naked bipolar nuclei.
**Represent myoepithelial cells stripped of their cytoplasm.
***Nuclei typically ovoid, may be spindle-shaped.


Images:
====Images====
*[http://commons.wikimedia.org/wiki/File:Breast_fibroadenoma_by_fine_needle_aspiration_%282%29_PAP_stain.jpg Fibroadenoma - FNA (WC)].
<gallery>
*[http://commons.wikimedia.org/wiki/File:Breast_fibroadenoma_by_fine_needle_aspiration_%281%29_DG_stain.jpg Fibroadenoma FNA - Diff-Quik (WC)].
Image:Breast_fibroadenoma_by_fine_needle_aspiration_%282%29_PAP_stain.jpg | Fibroadenoma - FNA (WC)
Image:Breast_fibroadenoma_by_fine_needle_aspiration_%281%29_DG_stain.jpg | Fibroadenoma FNA - Diff-Quik (WC)
</gallery>
www:
*[http://www.flickr.com/photos/jian-hua_qiao_md/3975095095/ Fibroadenoma (flickr.com)].


==Apocrine metaplasia/fibrocystic changes==
==Apocrine metaplasia/fibrocystic changes==
{{Main|Fibrocystic changes}}
===Cytology===
Features:<ref name=Ref_APBR677>{{Ref APBR|677}}</ref>
Features:<ref name=Ref_APBR677>{{Ref APBR|677}}</ref>
*Architecture - pretty much anything (flat, single, papillary, clusters, sheets).
*Architecture - pretty much anything (flat, single, papillary, clusters, sheets).
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**Vacuolated cytoplasm + round/oval nuclei.
**Vacuolated cytoplasm + round/oval nuclei.


Image:
====Image====
*[http://commons.wikimedia.org/wiki/File:Fibrocystic_changes_of_breast_-_cytology_1.jpg Oncocytes in FCC (WC)].
<gallery>
Image:Fibrocystic_changes_of_breast_-_cytology_1.jpg | Oncocytes in FCC. (WC)
</gallery>


==Paget's disease==
==Paget's disease==
{{Main|Paget disease of the breast}}
{{Main|Paget disease of the breast}}
===Cytology===
Features:<ref name=Ref_APBR677>{{Ref APBR|677}}</ref>
Features:<ref name=Ref_APBR677>{{Ref APBR|677}}</ref>
*Usually large cells with:
*Usually large cells with:
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==Papillary neoplasm==
==Papillary neoplasm==
===General===
*Location: retroareolar.
===Cytology===
Features:<ref name=ouhsc_35>URL: [http://moon.ouhsc.edu/kfung/jty1/CytoLearn/CytoQuiz/CQ-021-040/CQ-035-M.htm http://moon.ouhsc.edu/kfung/jty1/CytoLearn/CytoQuiz/CQ-021-040/CQ-035-M.htm]. Accessed on: 9 April 2012.</ref>
*Fibrovascular core - may not be evident.
*Cohesive cell clusters.
*+/-Single cells with cytoplasm.
DDx:
*Fibroadenoma - has single cells without cytoplasm.
====Image====
<gallery>
Image:Breast_papillary_neoplasm_1.jpg | Papillary neoplasm. (WC)
</gallery>
==Apocrine metaplasia==
===Cytology===
Features:
Features:
*Fibrovascular core - '''key feature'''.
*Nucleoli.
*Granular cytoplasm.


Image:
Image:
*[http://commons.wikimedia.org/wiki/File:Breast_papillary_neoplasm_1.jpg Papillary neoplasm (WC)].
*[http://www.womenshealthsection.com/content/art_images/20-47b.jpg Apocrine metaplasia (womenshealthsection.com)].<ref name=whs>URL: [http://www.womenshealthsection.com/content/print.php3?title=gynpc004&cat=60&lng=english http://www.womenshealthsection.com/content/print.php3?title=gynpc004&cat=60&lng=english]. Accessed on: 31 March 2012.</ref>
 
==Lactational changes==
{{Main|Lactational changes}}


==See also==
===General===
*May mimic ''ductal carcinoma''.
 
===Cytology===
Features:
*Nucleoli.
*Cytoplasmic vacuolization.
*Myoepithelial cells (bipolar cells) - '''important'''.
 
Notes:
*May for 3-D structures.
 
DDx:
*Ductal carcinoma.
 
=See also=
*[[Cytopathology]].
*[[Cytopathology]].
*[[Basics]].
*[[Basics]].
Line 167: Line 261:
*[[Breast cancer]].
*[[Breast cancer]].


==References==
=References=
{{reflist|2}}
{{reflist|2}}
=External links=
*[http://www.womenshealthsection.com/content/print.php3?title=gynpc004&cat=60&lng=english Breast cytopathology (womenshealthsection.com)].


[[Category:Cytopathology]]
[[Category:Cytopathology]]

Latest revision as of 00:22, 26 December 2014

Breast cytopathology, also breast cytology, is a relatively small part of cytopathology, as core biopsies are more in style.

This article deals only with breast cytopathology. An introduction to cytopathology is in the cytopathology article.

Overview

Common indications

  1. FNA done for a clinically benign lesion - unusual to find malignancy.
  2. FNA of a satellite lesion to assess extent of a presumed cancer; done together with a core biopsy of another site.

Pitfalls

False negative:

  • Lobular carcinoma - often single cells (may be in "chains"/"single file"), slightly hypercellular, cells appear bland/normal cytologically (if not carefully examined).[1]

Malignancy - the short version

  • If the cells are not dissociated... cancer is not likely.[2]
  • If there are stripped bipolar nuclei (these represent normal stromal cell) - cannot call overt malignancy.[3]

Normal breast

Features:

  • Sheets of flat cells.
  • Usu. no nucleoli.
  • Stripped bipolar (elliptical) nuclei.
  • +/-Adipose tissue:
    • Peripheral nucleus.
    • One large vacuole.

Notes:

  • Adipose tissue may represent a lipoma.

Breast cytopathology in a table

The common entities in breast cytopathology and their features:

Entity Key feature Architecture Cells Images
Normal Flat sheets of cells, stripped bipolar nuclei Flat sheets Uniform size, lack nucleolus
Fibroepithelial lesion (fibroadenoma, phyllodes) Clusters of cells with staghorn shape (jagged edge), bare bipolar nuclei Flat sheets & fluffy paucicellular (fibrous) tissue Mixed pop. in cluster; nuclei: oval/spindle (myoepi.) and round (epi.).
Fibroadenoma - FNA (WC)
Fibrocystic change Macrophages May have flat sheets of cells Oncocytic change (apocrine change) common, histocytes (foamy cytoplasm), nucleoli, large NCR
Oncocytes in FCC. (WC)
Papillary neoplasm Stalks (fibrovascular cores) Sheets, usu. flat? Variable size, nucleolus
Papillary neoplasm. (WC)
Ductal carcinoma Nuclear atypia, lack of stripped bipolar nuclei 3-D clusters Nuclear size variation, membrane irreg., nucleoli (prominent) - every cell, cell size var.
Ductal carcinoma. (WC)

Diagnoses

Fat necrosis of the breast

General

Etiology - various:[4]

  • Trauma.
  • Surgery.
  • Radiation.

Cytology

Features:[4]

  • Dying/dead adipocytes:
    • Light pink "low density" whispy poorly demarcated blobs - lack a nucleus.
      1. Early: cellular outlines seen, light pink/loose cytoplasm.
      2. Mid: cellular outlines indistinct, dense pink cytoplasm.
        • Foamy macrophages - adjacent to fat.
          • Abundant cytoplasm with granular (pink) crap inside.
          • Oval nucleus with small nucleolus.
      3. Late:
        • Macrophages: multinucleated giant-cells.
        • Calcification.
  • +/-Myospherulosis - granulomatous reaction of fat & blood.
    • Round aggregate of RBCs ~10-20 RBCs in diameter.

Notes:

  • Healthy adipocytes - large cells, clear cytoplasm.
  • Myospherulosis - due to exposure to fat, may be seen in the context of malignancy.[5]

Images

Ductal carcinoma

  • By convention one usually calls everything ductal carcinoma. It is the same as mammary carcinoma.

Cytology

Features:

  • Classic five:[6]
    1. Cellular size variation.
    2. Nuclear size variation.
      • May be marked adjacent cells different by factor of 2.
      • Typically not marked - often ~1.5.
    3. Nucleoli.
      • Should be in every cell.
      • Multiple suggestive of malignant.
    4. Irregular chromatin pattern.
    5. Lack of singular bipolar nuclei (in the background), key negative.
  • Other features:
    • 3-D clusters - strong indicator.
    • Cytoplasmic vacuoles - considered a classic finding.

Notes:

  • Typically single cells present.[7]
    • Exceptions are tubular carcinoma and colloid carcinoma; these have cells found in clusters or tubules/glands.[1]
  • Intracytoplasmic "lumens"/inclusions (think lobular carcinoma).
  • A useful rule of thumb: strongly suggestive of malignant ~3x RBC diameter & dyscohesive.[8]

DDx:

Images

Lobular carcinoma

Cytology

Features:

  • Discohesive, small, plasmacytoid cells.
  • Targetoid mucin - key features.

Tubular carcinoma

Cytology

Features:

  • Tubular structure with sharp point - key feature.

Mucinous carcinoma

Cytology

Features:

  • Mucin - blue/gray acellular material.
  • Nuclear atypia.

DDx:

  • Mucocele.

Fibroadenoma

General

  • Pitfall #1 for a malignant diagnosis, i.e. ductal carcinoma.

Cytology

Features:[9]

  • Flat sheets of cells with finger-link projections (called "antler horns") with a mixed cell population:
    • Cells with round nuclei (epithelium).
    • Cells with oval nuclei (myoepithelium).
  • Stromal fragments:
    • Spindle cells.
    • Fluffy appearance - relatively paucicellular.
  • Naked bipolar nuclei.
    • Represent myoepithelial cells stripped of their cytoplasm.
      • Nuclei typically ovoid, may be spindle-shaped.

Images

www:

Apocrine metaplasia/fibrocystic changes

Cytology

Features:[10]

  • Architecture - pretty much anything (flat, single, papillary, clusters, sheets).
  • Oncocytic change:
    • Finely granular cytoplasm - key feature.
    • Well-defined cell borders.
    • Nuclei round typically with one nucleolus (occasionally several nucleoli).
  • Macrophages (foamy) - key feature.
    • Vacuolated cytoplasm + round/oval nuclei.

Image

Paget's disease

Cytology

Features:[10]

  • Usually large cells with:
    • Nuclear atypia and nucleolus.
    • Abundant bubby (vacuolated) cytoplasm.
  • Malignant cell may have "cell-in-cell" arrangement.

Papillary neoplasm

General

  • Location: retroareolar.

Cytology

Features:[11]

  • Fibrovascular core - may not be evident.
  • Cohesive cell clusters.
  • +/-Single cells with cytoplasm.

DDx:

  • Fibroadenoma - has single cells without cytoplasm.

Image

Apocrine metaplasia

Cytology

Features:

  • Nucleoli.
  • Granular cytoplasm.

Image:

Lactational changes

General

  • May mimic ductal carcinoma.

Cytology

Features:

  • Nucleoli.
  • Cytoplasmic vacuolization.
  • Myoepithelial cells (bipolar cells) - important.

Notes:

  • May for 3-D structures.

DDx:

  • Ductal carcinoma.

See also

References

  1. 1.0 1.1 Lefkowitch, Jay H. (2006). Anatomic Pathology Board Review (1st ed.). Saunders. pp. 678. ISBN 978-1416025887.
  2. SM. 12 January 2010.
  3. SB. 27 January 2010.
  4. 4.0 4.1 Taboada, JL.; Stephens, TW.; Krishnamurthy, S.; Brandt, KR.; Whitman, GJ. (Mar 2009). "The many faces of fat necrosis in the breast.". AJR Am J Roentgenol 192 (3): 815-25. doi:10.2214/AJR.08.1250. PMID 19234281.
  5. Chau, KY.; Pretorius, JM.; Stewart, AW. (Oct 2000). "Myospherulosis in renal cell carcinoma.". Arch Pathol Lab Med 124 (10): 1476-9. doi:10.1043/0003-9985(2000)1241476:MIRCC2.0.CO;2. PMID 11035579.
  6. Sidawy, Mark K.; Ali, Syed Z. (2007). Fine Needle Aspiration Cytology: A Volume in Foundations in Diagnostic Pathology (1st ed.). Churchill Livingstone. pp. 137. ISBN 978-0443067310.
  7. Lefkowitch, Jay H. (2006). Anatomic Pathology Board Review (1st ed.). Saunders. pp. 678 (Q16). ISBN 978-1416025887.
  8. Chan, S. 26 April 2012.
  9. Lefkowitch, Jay H. (2006). Anatomic Pathology Board Review (1st ed.). Saunders. pp. 676. ISBN 978-1416025887.
  10. 10.0 10.1 Lefkowitch, Jay H. (2006). Anatomic Pathology Board Review (1st ed.). Saunders. pp. 677. ISBN 978-1416025887.
  11. URL: http://moon.ouhsc.edu/kfung/jty1/CytoLearn/CytoQuiz/CQ-021-040/CQ-035-M.htm. Accessed on: 9 April 2012.
  12. URL: http://www.womenshealthsection.com/content/print.php3?title=gynpc004&cat=60&lng=english. Accessed on: 31 March 2012.

External links