Merkel Cell Carcinoma of the Skin (excluding Merkel Cell Carcinoma of Penis, Scrotum, and Vulva)

Primary Site Histology Staging Type
C440, C442-C449 8247 TNM 7 and Summary Stage

If you are working with a site/histology that only summary stages and you need to directly code it, please use the SEER Summary Stage 2000 manual

Notes

C440 Skin of lip, NOS C442 External ear C443 Skin of ear and unspecified parts of face C444 Skin of scalp and neck C445 Skin of trunk C446 Skin of upper limb and shoulder C447 Skin of lower limb and hip C448 Overlapping lesion of skin C449 Skin, NOS **Note 1:** This schema is based on the UICC chapter *Merkel Cell Carcinoma of Skin,* pages 177-180. * This schema is NOT used for Merkel cell carcinoma of the penis, scrotum or vulva. Each of these has a separate schema. **Note 2:** Laterality must be coded for C442-C443 and C445-C447. For codes C443 and C445, if the tumor is midline (e.g., chin), code 5 (midline) in the laterality field. **Note 3:** Merkel cell carcinoma presenting in nodal or visceral site with primary site unknown is coded to C449, Skin, NOS. **Note 4:** In addition to directly assigning TNM, Summary Stage 2000 (SS2000) must be captured. If directly assigning SS2000, use the *Skin Except Eyelid* chapter on page 172 of the [SS2000 on-line manual](https://seer.cancer.gov/tools/ssm/ssm2000/SSSM2000-122012.pdf#page=172).

Main Data Items

Name Default Value Used for Staging NAACCR Item Required By Metadata
Clinical T <BLANK> Yes NAACCR #940
tnmClinT 		None
Clinical N <BLANK> Yes NAACCR #950
tnmClinN 		None
Clinical M <BLANK> Yes NAACCR #960
tnmClinM 		None
TNM Clin Stage Group 99 Yes NAACCR #970
tnmClinStageGroup 		None
Pathologic T <BLANK> Yes NAACCR #880
tnmPathT 		None
Pathologic N <BLANK> Yes NAACCR #890
tnmPathN 		None
Pathologic M <BLANK> Yes NAACCR #900
tnmPathM 		None
TNM Path Stage Group 99 Yes NAACCR #910
tnmPathStageGroup 		None
SSF1: Measured Thickness (Depth) 988 No NAACCR #2880
csSiteSpecificFactor1 		CCCR/Canada
COC		 None
SSF16: Size of Metastasis in Lymph Nodes 999 No NAACCR #2870
csSiteSpecificFactor16 		CCCR/Canada
COC
SEER		 None
SSF17: Extracapsular Extension of Regional Lymph Nodes 999 No NAACCR #2871
csSiteSpecificFactor17 		CCCR/Canada
COC
SEER		 None
SSF18: Isolated Tumor Cells (ITC) in Regional Lymph Node(s) 999 No NAACCR #2872
csSiteSpecificFactor18 		CCCR/Canada
COC
SEER		 None
SSF19: Tumor Base Transection Status 988 No NAACCR #2873
csSiteSpecificFactor19 		None None
SSF20: Tumor Infiltrating Lymphocytes (TIL) 988 No NAACCR #2874
csSiteSpecificFactor20 		None None
SSF21: Growth Pattern of Primary Tumor 988 No NAACCR #2875
csSiteSpecificFactor21 		None None
SSF22: Profound Immune Suppression 999 No NAACCR #2876
csSiteSpecificFactor22 		CCCR/Canada
COC
SEER		 None

Additional Data Items

Name Default Value Used for Staging NAACCR Item Required By Metadata
Year of Diagnosis <BLANK> No NAACCR #390
dateOfDiagnosis 		None
Primary Site <BLANK> Yes NAACCR #400
primarySite 		None
Histology <BLANK> Yes NAACCR #522
histologicTypeIcdO3 		None
Behavior <BLANK> Yes NAACCR #523
behaviorCodeIcdO3 		None
RX Summ Systemic/Surgery Sequence <BLANK> Yes NAACCR #1639
rxSummSystemicSurSeq 		None
RX Summ Surgery/Radiation Sequence <BLANK> Yes NAACCR #1380
rxSummSurgRadSeq 		None
Regional Nodes Positive <BLANK> Yes NAACCR #820
regionalNodesPositive 		None

Initial Context

Staging Methods

Expand All | Collapse All

TNM 7 Stage

Inclusion Table

Histology
8247

Start

Additional Context
Pathologic Stage Group = 90
Clinical Stage Group = 90

Next Step

  2. Parse T
  3. clin_t_prefix
    tmp_clin_t

Next Step

  2. Parse N Merkel (clin)
  3. clin_n_prefix
    tmp_clin_n

Next Step

  2. Parse M
  3. tmp_clin_m
    clin_m_prefix

Next Step

  2. Parse T
  3. tmp_path_t
    path_t_prefix

Next Step

  2. Parse N Merkel (path)
  3. tmp_path_n
    path_n_prefix

Next Step

  2. Parse M
  3. tmp_path_m
    path_m_prefix

Next Step

  2. Determine Default T
  3. Source T
    tmp_path_t
    tmp_clin_t
    tmp_combined_t

Next Step

  2. Determine Default N
  3. tmp_combined_n
    tmp_clin_n
    tmp_path_n
    Source N

Next Step

  2. Determine Default M
  3. tmp_path_m
    tmp_combined_m
    tmp_clin_m
    Source M

Next Step

  2. TNM 7 Stage Group
  3. Clinical Stage Group

Next Step

  2. TNM 7 Path Stage Group
  3. Pathologic Stage Group

Next Step

  2. Adjustments for No Clin or No Path
  3. tmp_combined_n
    tmp_combined_m
    Source T
    Clinical Stage Group
    Pathologic Stage Group
    Source N
    tmp_combined_t
    Source M

End

Combined Stage

Inclusion Table

Histology
8247

Start

Additional Context
Combined Stage Group = 90
Combined N = 90
Combined M = 90
Combined T = 90

Next Step

  2. Stop if No Clin and No Path
  3. Combined M
    Combined N
    Source T
    tmp_continue
    Combined T
    Combined Stage Group
    Source N
    Source M

Next Step

  2. Combined T
  3. Source T
    tmp_combined_t

Next Step

  2. Combined N for Tis Cancers
  3. tmp_combined_n
    Source N

Next Step

  2. Combined M
  3. tmp_combined_m
    tmp_source_m
    Source M

Next Step

  2. Determine Combined Prefix
  3. cmb_t_prefix

Next Step

  2. Determine Combined Prefix
  3. cmb_n_prefix

Next Step

  2. Determine Combined Prefix
  3. cmb_m_prefix

Next Step

  2. Concatenate T
  3. Combined T

Next Step

  2. Concatenate N
  3. Combined N

Next Step

  2. Concatenate M
  3. Combined M

Next Step

  2. TNM 7 Combined Stage Group
  3. Combined Stage Group

End

Outputs

Name Default Value Description NAACCR Item Metadata
Derived Version {{ctx_alg_version}} None None
Derived SEER Clin Stage Group 88 NAACCR #3610
derivedSeerClinStgGrp 		None
Derived SEER Path Stage Group 88 NAACCR #3605
derivedSeerPathStgGrp 		None
Derived SEER Combined Stage Group 88 NAACCR #3614
derivedSeerCmbStgGrp 		None
Derived SEER Combined T 88 NAACCR #3616
derivedSeerCombinedT 		None
Derived SEER Combined N 88 NAACCR #3618
derivedSeerCombinedN 		None
Derived SEER Combined M 88 NAACCR #3620
derivedSeerCombinedM 		None
Derived SEER Combined T Source <BLANK> NAACCR #3622
derivedSeerCmbTSrc 		None
Derived SEER Combined N Source <BLANK> NAACCR #3624
derivedSeerCmbNSrc 		None
Derived SEER Combined M Source <BLANK> NAACCR #3626
derivedSeerCmbMSrc 		None