Difference between revisions of "Merkel cell carcinoma"

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#redirect [[Dermatologic_neoplasms#Merkel_cell_carcinoma]]
'''Merkel cell carcinoma''', abbreviated '''MCC''', is an uncommon aggressive form of skin cancer.
 
==General==
Features:<ref name=pmid20418670>{{Cite journal  | last1 = Calder | first1 = KB. | last2 = Smoller | first2 = BR. | title = New insights into merkel cell carcinoma. | journal = Adv Anat Pathol | volume = 17 | issue = 3 | pages = 155-61 | month = May | year = 2010 | doi = 10.1097/PAP.0b013e3181d97836 | PMID = 20418670 }}</ref>
*Rare.
*Aggressive course/poor prognosis.
*Neuroendocrine-like.<ref name=pmid19395876>{{Cite journal  | last1 = Pulitzer | first1 = MP. | last2 = Amin | first2 = BD. | last3 = Busam | first3 = KJ. | title = Merkel cell carcinoma: review. | journal = Adv Anat Pathol | volume = 16 | issue = 3 | pages = 135-44 | month = May | year = 2009 | doi = 10.1097/PAP.0b013e3181a12f5a | PMID = 19395876 }}
</ref>
 
Etiology:
*Most caused by ''Merkel cell [[polyomavirus]]''.<ref name=pmid18202256>{{Cite journal  | last1 = Feng | first1 = H. | last2 = Shuda | first2 = M. | last3 = Chang | first3 = Y. | last4 = Moore | first4 = PS. | title = Clonal integration of a polyomavirus in human Merkel cell carcinoma. | journal = Science | volume = 319 | issue = 5866 | pages = 1096-100 | month = Feb | year = 2008 | doi = 10.1126/science.1152586 | PMID = 18202256 }}</ref><ref name=pmid20418670/>
*Immunocompromised/immunosuppressed (e.g. organ transplant recipients).
 
==Microscopic==
Features:<ref name=Ref_WMSP491>{{Ref WMSP|491}}</ref>
*Neuroendocrine nuclear features - round nucleus, small nucleoli/no nucleolus, stippled chromatin - '''key feature'''.
*Typically medium size cells ~3x resting lymphocyte.
**May be small or large.
*Architecture: nests, sheets or trabeculae.
*Scant cytoplasm.
*Abundant mitoses. †
*+/-Nuclear moulding.
**Nuclei of adjacent cells conform to one another.
*+/-Tumour infiltrating lymphocytes. ‡ 
 
Notes:
*† >10 mitoses/HPF = poor prognosis - definition suffers from [[HPFitis]].<ref name=capp_mcc>URL: [http://www.cap.org/apps/docs/committees/cancer/cancer_protocols /2011/SkinMerkelCell_11protocol.pdf http://www.cap.org/apps/docs/committees/cancer/cancer_protocols/2011/SkinMerkelCell_11protocol.pdf]. Accessed on: 28 March 2012.</ref>
*‡ May be associated with a worse prognosis.<ref name=capp_mcc/>
*Merkel cell carcinoma [[lymph node metastases]] is difficult to diagnose with routine stains; use of IHC stains are advised.<ref name=capp_mcc/>
*Arise from the epidermis - very rarely in situ.<ref name=pmid15606676>{{Cite journal  | last1 = Ferringer | first1 = T. | last2 = Rogers | first2 = HC. | last3 = Metcalf | first3 = JS. | title = Merkel cell carcinoma in situ. | journal = J Cutan Pathol | volume = 32 | issue = 2 | pages = 162-5 | month = Feb | year = 2005 | doi = 10.1111/j.0303-6987.2005.00270.x | PMID = 15606676 }}</ref>
 
DDx:
*[[Basal cell carcinoma]] - no stippled chromatin, less mitoses active.
*Cutaneous [[Ewing sarcoma]] - sorted-out with immunostains.
*[[Lymphoma]].
**[[Burkitt lymphoma]].
*Metastatic [[small cell carcinoma]].
*Other [[small round cell tumours]].
 
===Images===
<gallery>
Image:Merkel_cell_carcinoma_-_intermed_mag.jpg | MCC - intermed. mag. (WC/Nephron)
Image:Merkel_cell_carcinoma_-_very_high_mag.jpg | MCC - very high mag. (WC/Nephron)
Image:Merkelcellcarcinoma_Tag.jpg | Merkel cell carcinoma - nested pattern (WC)
</gallery>
www:
*[http://www.bccancer.bc.ca/HPI/CE/cytotechnology/cytosleuthquiz/nongyne/ng12hist.htm MCC (bccancer.bc.ca)].
*[http://www.joplink.net/prev/200403/07.html MCC (joplink.net)].
*[http://www.ispub.com/ispub/ijd/volume_5_number_2_8/concurrent_merkel_cell_carcinoma_and_bowen_s_disease_of_the_thigh/bowen-fig3.jpg Merkel cell carcinoma (ispub.com)].
*[http://path.upmc.edu/cases/case398.html Merkel cell carcinoma - several images (upmc.edu)].
 
==IHC==
Features:
*CK7 -ve.
*CK20 +ve (perinuclear dot-like).<ref name=pmid11533085>{{Cite journal  | last1 = Leech | first1 = SN. | last2 = Kolar | first2 = AJ. | last3 = Barrett | first3 = PD. | last4 = Sinclair | first4 = SA. | last5 = Leonard | first5 = N. | title = Merkel cell carcinoma can be distinguished from metastatic small cell carcinoma using antibodies to cytokeratin 20 and thyroid transcription factor 1. | journal = J Clin Pathol | volume = 54 | issue = 9 | pages = 727-9 | month = Sep | year = 2001 | doi =  | PMID = 11533085 | URL = http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1731517/  }}</ref>
*CAM5.2 +ve (dot-like pattern).
*CD56 +ve.
*AE1/AE3 +ve.
*Merkel cell polyomavirus +ve ~85% of cases.<ref name=pmid21870327>{{Cite journal  | last1 = Jung | first1 = HS. | last2 = Choi | first2 = YL. | last3 = Choi | first3 = JS. | last4 = Roh | first4 = JH. | last5 = Pyon | first5 = JK. | last6 = Woo | first6 = KJ. | last7 = Lee | first7 = EH. | last8 = Jang | first8 = KT. | last9 = Han | first9 = J. | title = Detection of Merkel cell polyomavirus in Merkel cell carcinomas and small cell carcinomas by PCR and immunohistochemistry. | journal = Histol Histopathol | volume = 26 | issue = 10 | pages = 1231-41 | month = Oct | year = 2011 | doi =  | PMID = 21870327 }}</ref>
 
Others:
*TTF-1 -ve.
*NSE +ve.<ref name=pmid15606676/>
 
==EM==
*''[[Neurosecretory granules]]'' ([[AKA]] dense-core granules).<ref name=pmid9062165>{{Cite journal  | last1 = Gil-Moreno | first1 = A. | last2 = Garcia-Jiménez | first2 = A. | last3 = González-Bosquet | first3 = J. | last4 = Esteller | first4 = M. | last5 = Castellví-Vives | first5 = J. | last6 = Martínez Palones | first6 = JM. | last7 = Xercavins | first7 = J. | title = Merkel cell carcinoma of the vulva. | journal = Gynecol Oncol | volume = 64 | issue = 3 | pages = 526-32 | month = Mar | year = 1997 | doi =  | PMID = 9062165 }}</ref>
 
==See also==
*[[Dermatologic neoplasms]].
*[[Small cell carcinoma]].
 
==References==
{{Reflist|2}}


[[Category:Diagnosis]]
[[Category:Diagnosis]]
[[Category:Dermatopathology]]

Revision as of 23:16, 21 August 2013

Merkel cell carcinoma, abbreviated MCC, is an uncommon aggressive form of skin cancer.

General

Features:[1]

  • Rare.
  • Aggressive course/poor prognosis.
  • Neuroendocrine-like.[2]

Etiology:

  • Most caused by Merkel cell polyomavirus.[3][1]
  • Immunocompromised/immunosuppressed (e.g. organ transplant recipients).

Microscopic

Features:[4]

  • Neuroendocrine nuclear features - round nucleus, small nucleoli/no nucleolus, stippled chromatin - key feature.
  • Typically medium size cells ~3x resting lymphocyte.
    • May be small or large.
  • Architecture: nests, sheets or trabeculae.
  • Scant cytoplasm.
  • Abundant mitoses. †
  • +/-Nuclear moulding.
    • Nuclei of adjacent cells conform to one another.
  • +/-Tumour infiltrating lymphocytes. ‡

Notes:

  • † >10 mitoses/HPF = poor prognosis - definition suffers from HPFitis.[5]
  • ‡ May be associated with a worse prognosis.[5]
  • Merkel cell carcinoma lymph node metastases is difficult to diagnose with routine stains; use of IHC stains are advised.[5]
  • Arise from the epidermis - very rarely in situ.[6]

DDx:

Images

  • MCC - intermed. mag. (WC/Nephron)

  • MCC - very high mag. (WC/Nephron)

  • Merkel cell carcinoma - nested pattern (WC)

www:

IHC

Features:

  • CK7 -ve.
  • CK20 +ve (perinuclear dot-like).[7]
  • CAM5.2 +ve (dot-like pattern).
  • CD56 +ve.
  • AE1/AE3 +ve.
  • Merkel cell polyomavirus +ve ~85% of cases.[8]

Others:

  • TTF-1 -ve.
  • NSE +ve.[6]

EM

See also

References

  1. ↑ 1.0 1.1 Calder, KB.; Smoller, BR. (May 2010). "New insights into merkel cell carcinoma.". Adv Anat Pathol 17 (3): 155-61. doi:10.1097/PAP.0b013e3181d97836. PMID 20418670.
  2. ↑ Pulitzer, MP.; Amin, BD.; Busam, KJ. (May 2009). "Merkel cell carcinoma: review.". Adv Anat Pathol 16 (3): 135-44. doi:10.1097/PAP.0b013e3181a12f5a. PMID 19395876.
  3. ↑ Feng, H.; Shuda, M.; Chang, Y.; Moore, PS. (Feb 2008). "Clonal integration of a polyomavirus in human Merkel cell carcinoma.". Science 319 (5866): 1096-100. doi:10.1126/science.1152586. PMID 18202256.
  4. ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 491. ISBN 978-0781765275.
  5. ↑ 5.0 5.1 5.2 URL: /2011/SkinMerkelCell_11protocol.pdf http://www.cap.org/apps/docs/committees/cancer/cancer_protocols/2011/SkinMerkelCell_11protocol.pdf. Accessed on: 28 March 2012.
  6. ↑ 6.0 6.1 Ferringer, T.; Rogers, HC.; Metcalf, JS. (Feb 2005). "Merkel cell carcinoma in situ.". J Cutan Pathol 32 (2): 162-5. doi:10.1111/j.0303-6987.2005.00270.x. PMID 15606676.
  7. ↑ Leech, SN.; Kolar, AJ.; Barrett, PD.; Sinclair, SA.; Leonard, N. (Sep 2001). "Merkel cell carcinoma can be distinguished from metastatic small cell carcinoma using antibodies to cytokeratin 20 and thyroid transcription factor 1.". J Clin Pathol 54 (9): 727-9. PMID 11533085.
  8. ↑ Jung, HS.; Choi, YL.; Choi, JS.; Roh, JH.; Pyon, JK.; Woo, KJ.; Lee, EH.; Jang, KT. et al. (Oct 2011). "Detection of Merkel cell polyomavirus in Merkel cell carcinomas and small cell carcinomas by PCR and immunohistochemistry.". Histol Histopathol 26 (10): 1231-41. PMID 21870327.
  9. ↑ Gil-Moreno, A.; Garcia-Jiménez, A.; González-Bosquet, J.; Esteller, M.; Castellví-Vives, J.; Martínez Palones, JM.; Xercavins, J. (Mar 1997). "Merkel cell carcinoma of the vulva.". Gynecol Oncol 64 (3): 526-32. PMID 9062165.
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