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Difference between revisions of "Merkel cell carcinoma"
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'''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]] | |||