What thoracic malignancy is Merkel cell carcinoma related to?
Skin
Merkel Cell Carcinoma
No
U
D
Merkel cell carcinoma (MCC) is often referred to as cutaneous neuroendocrine carcinoma and was originally referred to as trabecular carcinoma. MCC derives from Merkel cells which reside in the basal layer of the epidermis. Merkel cells play a role in mechanoreception and possibly a neuroendocrine role in the skin. They are morphologically difficult to distinguish from basal cells and melanocytes. Histologic characteristics of MCC include large nuclei and prominent nucleoli. MCC can be easily confused with metastatic small cell carcinoma. Some publications refer to it as cutaneous small cell carcinoma. MCC is derived from embryologic neural crest cells and may share some lineage with small cell carcinoma.
Important immunohistochemical differences allow us to accurately identify MCC. The malignant cells will usually (~95%) stain positive for CK-20 and negative for TTF-1, whereas small cell carcinoma is negative for CK-20 and positive for TTF-1 is most cases. MCC should be negative for CK-7. This differentiates it from small cell carcinoma. MCC is also negative for leukocyte common antigen (LCA) which is positive in lymphoma.
Heads up! You can use keyboard for test navigation: press → for Next,
← for Previous, M for Mark/Unmark, P for Pause,
R for Review, A,B,C,... or 1,2,3,... to select answer.
