Skin - Nonmelanocytic tumors
Carcinoma (non-adnexal)
Merkel cell carcinoma - staging

Author: Ghassan Tranesh, M.D. (see Authors page)
Editor: Hong Qu, M.D.

Revised: 13 October 2016, last major update December 2014

Copyright: (c) 2002-2016,, Inc.

PubMed Search: Merkel cell carcinoma [title] staging

Cite this page: Merkel cell carcinoma - staging. website. Accessed December 12th, 2018.
Definition / general
  • TNM Descriptors (required only if applicable)
    • m (multiple)
    • r (recurrent)
    • y (post-treatment)

  • Primary Merkel Cell Carcinoma Pathologic Stage (pT)
    • pTX: Primary MCC cannot be assessed
    • pT0: No evidence of MCC
    • pTis: In situ primary tumor
    • pT1: Less than or equal to 2 cm maximum MCC dimension
    • pT2: Greater than 2 cm but not more than 5 cm maximum tumor dimension
    • pT3: More than 5 cm maximum tumor dimension
    • pT4: Primary tumor invades adjacent tissue e.g. bone, muscle, fascia, or cartilage

  • Regional Lymph Nodes (pN)
    • pNX: Nodes not examined pathologically
    • pN0: Nodes negative by pathologic examination
    • pN1: Metastasis in regional lymph nodes
    • pN1a: Micrometastasis
    • pN1b: Macrometastasis
    • pN2: Transient nodal metastasis

  • Distant Metastasis (pM)
    • Not applicable
    • pM1: Metastasis beyond regional lymph nodes
    • pM1a: Metastasis to skin, subcutaneous tissues, or distant lymph nodes
    • pM1b: Metastasis to lungs
    • pM1c: Metastasis to visceral sites

  • Stage grouping:
    • Stage 0: Tis N0 M0
    • Stage IA: T1 pN0 M0
    • Stage IB: T1 cN0 M0
    • Stage IIA: T2-3 pN0 M0
    • Stage IIB: T2-3 cN0 M0
    • Stage IIC: T4 N0 M0
    • Stage IIIA: Any T N1a M0
    • Stage IIIB: Any T N1b/N2 M0
    • Stage IV: M1 (Any T, Any N)