Case Number : Case 2989 - 21 December 2021 Posted By: Uma Sundram

Sorry. I’m an old pathologist. Sorry again. But for me this is a Merkel cell carcinoma. Not CK20+ ? I don’t know why. But this is a MCC. 

1 hour ago, vincenzo said:

Sorry. I’m an old pathologist. Sorry again. But for me this is a Merkel cell carcinoma. Not CK20+ ? I don’t know why. But this is a MCC. 

Could be due to,

An Unusual Immunohistochemical Profile (CK7+/CK20-) for Merkel Cell Carcinoma 

https://academic.oup.com/ajcp/article/144/suppl_2/A270/1775548

Thanks Eman. Thanks a lot. 

CK7-positive/CK20-negative phenotype is seen in a wide variety of carcinomas, including carcinomas of the lung, breast, thyroid, pancreas, and female genital tract

any imaging data available

INSM 1 positivity is a feature of neuroendocrine and neuroepithelial tumours. Search for primary is the way forward.

An unusual and difficult. Patient has a history of Merkel ce'll carcinoma. We obtained the prior and her Merkel cell has a completely different morphology. She also has highly aggressive local SCC. Our final diagnosis=poorly differentiated carcinoma, SCC vs neuroendocrine. The latter is not favored but cannot be excluded.

Thank you for your comments.

Thanks a lot for the case