]> M-8935-8936 C48.0 Retroperitioneum C48.1 Specified parts of peritoneum (including omentum and mesentery) C48.2 Peritoneum, NOS C48.8 Overlapping lesion of retroperitoneum and peritoneum &commontumorsizegistperitoneum; CS Extension Note: The assignment of T categories for gastrointestinal stromal tumors (GIST) is based on tumor size. A physician's statement of the T category may be used to code CS Tumor Size and/or CS Extension if this is the only information in the medical record regarding one or both of these fields. However the two fields are coded independently: for example the record may document size but not extension, other than the physician's statement of the T category. Use codes 350. 360, 370, and 380 as appropriate to code CS Extension based on a statement of T when no other extension information is available. Code Description TNM 7 Map TNM 6 Map SS77 Map SS2000 Map 100 ^ * L L 300 Localized, NOS ^ * L L 350 Stated as T1 with no other information on extension ^ * L L 360 Stated as T2 with no other information on extension ^ * L L 370 Stated as T3 with no other information on extension ^ * L L 380 Stated as T4 with no other information on extension ^ * L L 400 Adjacent connective tissue ^ * RE RE 500 ERROR ERROR ERROR ERROR 510 ERROR ERROR ERROR ERROR 520 ERROR ERROR ERROR ERROR 600 ^ * RE RE 800 ^ * D D 950 No evidence of primary tumor T0 T0 U U 999 TX TX U U ^ For CS Extension codes 100-800 ONLY, the T category for AJCC 7 staging is assigned based on the value of CS Tumor Size, as shown in the Extension Size AJCC 7 Table for this schema. * For CS Extension codes 100-800 ONLY, the T category for AJCC 6 staging is assigned based on the value of CS Tumor Size, as shown in the Extension Size AJCC 6 Table for this schema. &generalcstsexteval; CS Lymph Nodes Note 1: Code only regional nodes and nodes, NOS in this field. Distant nodes are coded in CS Mets at DX. Note 2: Nodal metastasis is very rare in gastrointestinal stromal tumors, and surgeons generally agree that nodal dissection is not indicated. In the absence of information on regional lymph node status, N0 is appropriate; code 999 is mapped to N0 accordingly. Code Description TNM 7 Map TNM 6 Map SS77 Map SS2000 Map 000 No regional lymph node involvement N0 N0 NONE NONE 100 N1 N1 RN RN 800 Lymph nodes, NOS N1 N1 RN RN 999 N0 NX U U &generalregnodeseval; &generalreglnpos; &generalreglnexam; CS Mets at DX Note 1: Liver metastasis implies the presence of tumor inside the liver parenchyma as one or more nodules. Adherence to the liver capsule, even if extensive, should not be considered distant metastasis. Code direct adherence to the liver in CS Extension code 600. Code Description TNM 7 Map TNM 6 Map SS77 Map SS2000 Map 00 No distant metastasis M0 M0 NONE NONE 10 Distant lymph node(s) M1 M1 D D 40 M1 M1 D D 45 M1 M1 D D 50 M1 M1 D D 60 M1 M1 D D 99 M0 MX U U &generalmetseval; ¬appssfactor1; ¬appssfactor2; ¬appssfactor3; ¬appssfactor4; CS Site-Specific Factor 5 Mitotic Count Note 1: The mitotic rate (the count of mitoses per 50 high-power fields or 50 HPF) reflects the potential aggressiveness or prognosis of gastrointestinal stromal tumors (GIST), and is used alone to determine their histologic grade (low or high). The mitotic rate is also a factor in assigning the AJCC 7 anatomic stage/prognostic group. This site-specific factor presumes the denominator of 50 HPF or its equivalent, so just the numerator (the mitotic count) is coded here. Note 2: A HPF usually has a magnification objective of 40 (a 40x field). As described in the AJCC chapter on GIST, 50 HPF are equivalent to viewing a total area of 5 square millimeters (mm) at 40x magnification. Note 3: Record mitotic count, to the nearest tenth of a mitosis, as documented in the pathology report. For example, a mitotic count of 6/50 HPF, or 6 per 5 square mm, would be coded 060. Note 4: Code the specific mitotic count only per 50 HPF or 5 square mm; assume the denominator is 50 HPF or 5 square mm if not specified. Use code 996 only if the mitotic count is expressed with a specific denominator other than 50 HPF or 5 square mm. Code Description 000 001-008 009 010-100 110 888 988 990 991 995 996 998 999 CS Site-Specific Factor 6 KIT Gene Immunohistochemistry (IHC) Note 1: Most gastrointestinal stromal tumors (GISTs) have oncogenic mutations of the KIT gene, which is located on chromosome 4q. KIT is a cytokine receptor which binds to stem cell factor, which causes certain types of cells to grow; altered forms of KIT may be associated with some types of cancer. This test detects expression of the KIT gene in tumor tissue sections using immunohistochemical (IHC) stains. Test results are available in the pathology report. A positive test helps to establish the diagnosis of GIST and to identify patients for whom treatment with agents such as imatinib mesylate (Gleevec) or sunitinib malate (Sutent) is appropriate. Do not record secondary or acquired mutations that may have developed because of long-term imatinib treatment. Note 2: Another name for KIT is CD117. Note 3: See CS Site-Specific Factor 7 for coding information about specific mutations of the KIT gene detectable with molecular testing. See CS Site-Specific Factor 8 for coding information about mutations of the PDGFRA gene. Code Description 010 Positive/elevated 020 Negative/normal; within normal limits 030 Borderline; undetermined whether positive or negative 888 988 997 Test ordered, results not in chart; results pending 998 Test not done (test not ordered and not performed) 999 CS Site-Specific Factor 7 KIT Gene Mutations Note 1: This is a special molecular diagnostic test performed on tumor tissue to identify mutations in specific parts (called exons) of the KIT gene. Certain patterns of mutations correlate with the anatomic site and morphology of gastrointestinal stromal tumors (GISTs) tumors and can predict response to treatment with agents such as imatinib mesylate (Gleevec) and sunitinib malate (Sutent). Some mutations are associated with acquired resisteance to imatinib treatment; do not record secondary or acquired mutations that may have been caused by long-term imatinib treatment. Note 2: Code the mutation locations found from the KIT gene test. Another name for KIT is CD117. Note 3: See CS Site-Specific Factor 6 for coding information about KIT expression detected with immunohistochemistry (IHC). See CS Site-Specific Factor 8 for coding information about mutations of the PDGFRA gene. Code Description 000 KIT gene test negative for mutations; no mutations; normal or wild-type gene 010 KIT gene test positive for mutation of exon 9 only 020 KIT gene test positive for mutation of exon 11 only 030 KIT gene test positive for mutation of exon 13 only 040 KIT gene test positive for mutation of exon 17 only 800 KIT gene test positive for one other specified mutation 810 KIT gene test performed, positive for more than one specific mutation 850 KIT gene test positive, NOS; mutation(s) found but the specific mutation(s) are not stated 988 997 Test ordered, results not in chart; results pending 998 Test not done (test not ordered and not performed) 999 CS Site-Specific Factor 8 PDGFRA Gene Mutation Note 1: Some gastrointestinal stromal tumors (GISTs) have oncogenic mutations of the platelet-derived growth factor receptor alpha (PDGFRA)gene, located on chromosome 4q. This test is a special molecular diagnostic test performed on tumor tissue to identify PDGFRA mutations. Some GISTs that are negative for KIT mutations are positive for PDGFRA mutation. Note 2: Code the result of the PDGFRA gene test. Another name for PDGFRA is CD140A. Note 3: See CS Site-Specific Factors 6 and 7 for coding information about KIT gene expression and mutations. Code Description 010 PDGFRA gene test positive for mutations 020 PDGFRA gene test negative for mutations; no mutations; normal or wild-type gene 988 997 Test ordered, results not in chart; results pending 998 Test not done (test not ordered and not performed) 999 CS Site-Specific Factor 9 Tumor Multiplicity Code Description 000 Multiple gastrointestinal stromal tumors (GIST) not present in the surgical specimen; single GIST; unifocal GIST 010 Multiple GIST tumors present in the surgical specimen; multifocal GIST 988 999 &commonssf10gistperitoneum; ¬appnewssf11; ¬appnewssf12; ¬appnewssf13; ¬appnewssf14; ¬appnewssf15; ¬appnewssf16; ¬appnewssf17; ¬appnewssf18; ¬appnewssf19; ¬appnewssf20; ¬appnewssf21; ¬appnewssf22; ¬appnewssf23; ¬appnewssf24; ¬appnewssf25; &commonhistinclusiongist; &commonhistexclusionssarcoma; &commonstagegistintestinetnm7; &commonstageheartmedperit; &commonsummarystage; AJCC TNM 7 Stage - GIST Stomach T N M Mitotic Rate Stage T0 N0 M0 Low ERROR T0 N0 M0 High ERROR T0 N0 M0 Unknown ERROR T0 N1 M0 Low IV T0 N1 M0 High IV T0 N1 M0 Unknown IV T1 N0 M0 Low IA T1 N0 M0 High II T1 N0 M0 Unknown UNK T1 N1 M0 Low IV T1 N1 M0 High IV T1 N1 M0 Unknown IV T2 N0 M0 Low IA T2 N0 M0 High II T2 N0 M0 Unknown UNK T2 N1 M0 Low IV T2 N1 M0 High IV T2 N1 M0 Unknown IV T3 N0 M0 Low IB T3 N0 M0 High IIIA T3 N0 M0 Unknown UNK T3 N1 M0 Low IV T3 N1 M0 High IV T3 N1 M0 Unknown IV T4 N0 M0 Low II T4 N0 M0 High IIIB T4 N0 M0 Unknown UNK T4 N1 M0 Low IV T4 N1 M0 High IV T4 N1 M0 Unknown IV TX N0 M0 Low UNK TX N0 M0 High UNK TX N0 M0 Unknown UNK TX N1 M0 Low IV TX N1 M0 High IV TX N1 M0 Unknown IV T0 N0 M1 Low IV T0 N0 M1 High IV T0 N0 M1 Unknown IV T0 N1 M1 Low IV T0 N1 M1 High IV T0 N1 M1 Unknown IV T1 N0 M1 Low IV T1 N0 M1 High IV T1 N0 M1 Unknown IV T1 N1 M1 Low IV T1 N1 M1 High IV T1 N1 M1 Unknown IV T2 N0 M1 Low IV T2 N0 M1 High IV T2 N0 M1 Unknown IV T2 N1 M1 Low IV T2 N1 M1 High IV T2 N1 M1 Unknown IV T3 N0 M1 Low IV T3 N0 M1 High IV T3 N0 M1 Unknown IV T3 N1 M1 Low IV T3 N1 M1 High IV T3 N1 M1 Unknown IV T4 N0 M1 Low IV T4 N0 M1 High IV T4 N0 M1 Unknown IV T4 N1 M1 Low IV T4 N1 M1 High IV T4 N1 M1 Unknown IV TX N0 M1 Low IV TX N0 M1 High IV TX N0 M1 Unknown IV TX N1 M1 Low IV TX N1 M1 High IV TX N1 M1 Unknown IV Extension Size AJCC 7 Table Note: For CS Extension codes 100-800 only, the T category for AJCC 7 staging is assigned based on the value of Tumor Size as shown in this table. CS Extension CS Tumor Size 000 0 CS Tumor Size 001-020 1 20 CS Tumor Size 021-050 21 50 CS Tumor Size 051-100 51 100 CS Tumor Size 101-989 101 989 CS Tumor Size 990-991 990 991 CS Tumor Size 992 992 CS Tumor Size 993 993 CS Tumor Size 994-995 994 995 CS Tumor Size 996 996 CS Tumor Size 997 997 CS Tumor Size 998 998 CS Tumor Size 999 999 100 ERROR T1 T2 T3 T4 T1 T1 T2 T2 T3 T4 ERROR TX 300 ERROR T1 T2 T3 T4 T1 T1 T2 T2 T3 T4 ERROR TX 350 ERROR T1 T2 T3 T4 T1 T1 T2 T1 T1 T1 ERROR T1 360 ERROR T1 T2 T3 T4 T1 T2 T2 T2 T2 T2 ERROR T2 370 ERROR T1 T2 T3 T4 T1 T3 T2 T3 T3 T3 ERROR T3 380 ERROR T1 T2 T3 T4 T1 T4 T2 T4 T4 T4 ERROR T4 400 ERROR T1 T2 T3 T4 T1 T1 T2 T2 T3 T4 ERROR TX 600 ERROR T1 T2 T3 T4 T1 T1 T2 T2 T3 T4 ERROR TX 800 ERROR T1 T2 T3 T4 T1 T1 T2 T2 T3 T4 ERROR TX Extension Size AJCC 6 Table Note: For CS Extension codes 100-800, the T category for AJCC 6 staging is assigned based on the value of CS Tumor Size, as shown in this table. CS Extension CS Tumor Size 000 0 CS Tumor Size 001-050 1 50 CS Tumor Size 051-989 51 989 CS Tumor Size 990-995 990 995 CS Tumor Size 996-997 996 997 CS Tumor Size 998 998 CS Tumor Size 999 999 100 ERROR T1b T2b T1b T2b ERROR TX 300 ERROR T1b T2b T1b T2b ERROR TX 350 ERROR T1b T2b T1b T2b ERROR T1b 360 ERROR T1b T2b T1b T2b ERROR T1b 370 ERROR T1b T2b T1b T2b ERROR T2b 380 ERROR T1b T2b T1b T2b ERROR T2b 400 ERROR T1b T2b T1b T2b ERROR TX 600 ERROR T1b T2b T1b T2b ERROR TX 800 ERROR T1b T2b T1b T2b ERROR TX Mitotic Rate Calculation Table Note: The Mitotic Count recorded in CS Site-Specific Factor 5 is used to determine the Mitotic Rate as shown in this table. The Mitotic Rate from the Mitotic Rate Calculation Table, "low" or "high", is used in the calculation of the AJCC TNM 7 stage group as shown in the AJCC TNM 7 Stage tables. CS SSF 5 Mitotic Count Mitotic Rate 000-050 Low 051-100 High 110 High 888 ERROR 988 Low 990 Low 991 High 995 ERROR 996 Unknown 998 Unknown 999 Unknown