Seattle Multidisciplinary MCC TeamUniversity of Washington MCC ResearchFred Hutchinson Cancer Research Center Seattle Cancer Care Alliance/Skin Cancer

The diagnosis of MCC is made with a skin biopsy, which is examined under the microscope. Special stains are used to distinguish MCC from other forms of cancer, such as small cell lung cancer (SCLC), lymphoma, and small cell melanoma. Each of these cancers has a unique profile as defined by special stains (see table below). MCC will stain for low molecular weight cytokeratins (CAM 5.2 or AE1/AE3), CK 20 and neuron-specific enolase (NSE) (see photographs below). MCC will not stain for CK7 or thyroid transcription factor 1 (TTF-1) (positive in SCLC), leukocyte common antigen (LCA) (positive in lymphoma) and S100 (positive in small cell melanoma).

Biopsy Characteristics for MCC and Tumors Resembling MCC
 

Stain

Tumor CAM5.2 or
AE1/AE3
CK20 NSE CK7 or
TTF-1
LCA S100
   MCC

+

+

+

-

-

-

   SCLC

+

-

+

+

-

-

   Lymphoma

-

-

-

-

+

-

   Melanoma

-

-

+

-

-

+

SCLC = small cell lung cancer

MCC as stained by A) hemotoxylin & eosin, B) CAM 5.2, C) CK 20, and D) NSE (Goessling, 2002 & Nghiem, 2001).