Merkel cell carcinoma is staged by tumour size (2 cm is the cut-off), growth into deeper tissue, spread to lymph nodes and, at stage IV, to distant skin or organs.
AJCC chapter 46 covers Merkel cell carcinoma and is an 8th edition chapter in the AJCC 2026 table. In the NCI's summary, stage 0 is abnormal Merkel cells in the top layer of skin; stage I is a tumour of 2 cm or less; IIA larger than 2 cm; IIB spread into connective tissue, muscle, cartilage or bone; stage III adds lymph node spread; stage IV is spread to skin away from the primary tumour or to organs such as liver, lung, bone or brain. The stage descriptions are those in the National Cancer Institute's PDQ summary, which follows the AJCC tables.
Each skin cancer comes from a different cell layer: melanocytes and basal cells at the base of the epidermis, keratinocytes above them, Merkel cells and blood vessels in the dermis; depth of invasion decides the risk.
Same organ: Melanoma, Basal cell carcinoma, Cutaneous squamous cell carcinoma, Kaposi sarcoma, Skin cancer (all types), BRAF V600-mutant melanoma, Stage III melanoma (after surgery), Stage IIB and IIC melanoma, Advanced melanoma (unresectable stage III and stage IV), Mucosal melanoma, Acral melanoma, Advanced cutaneous squamous cell carcinoma, Locally advanced and metastatic basal cell carcinoma, Bowen's disease (squamous cell carcinoma in situ), Dermatofibrosarcoma protuberans
Showing the organ this term concerns: Merkel cell carcinoma.
Shares Disease-specific staging and risk systems (FIGO, Ann Arbor, IPI, R-ISS, ELN, IMDC), TNM staging.
Shares Disease-specific staging and risk systems (FIGO, Ann Arbor, IPI, R-ISS, ELN, IMDC), TNM staging.
Shares Disease-specific staging and risk systems (FIGO, Ann Arbor, IPI, R-ISS, ELN, IMDC), TNM staging.
Shares Disease-specific staging and risk systems (FIGO, Ann Arbor, IPI, R-ISS, ELN, IMDC), TNM staging.
Shares Disease-specific staging and risk systems (FIGO, Ann Arbor, IPI, R-ISS, ELN, IMDC), TNM staging.
Shares Disease-specific staging and risk systems (FIGO, Ann Arbor, IPI, R-ISS, ELN, IMDC), TNM staging.
Shares Disease-specific staging and risk systems (FIGO, Ann Arbor, IPI, R-ISS, ELN, IMDC), TNM staging.
Shares Disease-specific staging and risk systems (FIGO, Ann Arbor, IPI, R-ISS, ELN, IMDC), TNM staging.
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