Clinical signs:
Histology:
Sheets of small, round cells with narrow cytoplasm; high mitotic activity; inconspicuous nucleoli; positivity for NSE, chromogranin, CD57; paranuclear positivity for cytokeratin 20.
Pictures
Merkel cell carcinoma:
Merkel cell carcinoma, HE 10x (1443)
Merkel cell carcinoma, HE 20x (1444)Merkel cell carcinoma, HE 40x (1445)Merkel cell carcinoma, CK20 20x (1793)Merkel cell carcinoma, CK20 100x (1792)
Another case:
Merkel cell carcinoma, HE 40x (2003)Merkel cell carcinoma, HE 40x (2004)
Another case, trabecular tumor:
Merkel cell carcinoma, eyelid, HE 10x (2530)Merkel cell carcinoma, eyelid, HE 40x (2532)Merkel cell carcinoma, eyelid, HE 100x (2531)Merkel cell carcinoma, CK20 100x (2560)Merkel cell carcinoma, chromogranin 40x (2561)Merkel cell carcinoma, AE13 40x (2547)
Another case:
Merkel cell carcinoma, HE 20x (4814) [zoomify]Merkel cell carcinoma, HE 20x (4536) [zoomify]Merkel cell carcinoma, CK20 20x (4813) [zoomify]
Another case:
Merkel cell carcinoma, HE 20x (5363)
Another case:
Merkel cell carcinoma, HE 20x (6204)Merkel cell carcinoma, HE 40x (6219)
Another case:
Merkel cell carcinoma, HE 40x (6451)Merkel cell carcinoma, NSE 40x (6444)Merkel cell carcinoma, CK20 40x (6443)
Another case:
Merkel cell carcinoma, HE 60x (10053)Merkel cell carcinoma, CK20 60x (10052)
Another case, strong CD20 positivity:
Merkel cell carcinoma, HE 60x (13955)Merkel cell carcinoma, CK20 60x (13954)
Another case:
Merkel cell carcinoma, HE 40x (12915)Merkel cell carcinoma, HE 40x (12916)
Combination of Merkel cell carcinoma and squamous cell carcinoma:
Merkel cell carcinoma and squamous cell carcinoma, HE 40x (13303)Merkel cell carcinoma and squamous cell carcinoma, HE 40x (13304)Merkel cell carcinoma and squamous cell carcinoma, CK20 40x (13302)