CS Mets at DX

Notes

**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 liver metastasis. Code direct adherence to the liver in CS Extension code 600. **Note 2**: When a patient has more than one area of GIST, it is important to try to distinguish between intra-abdominal metastasis and tumor multiplicity. Distant metastases are relatively rare in GISTs, but they are increasingly detected with sophisticated radiological studies. Intra-abdominal metastasis will present as tumor involvement in the abdominal cavity outside the main tumor mass, in the peritoneum, omentum, serosae of organs, and the cul-de-sac, among other areas. Code this form of metastasis in CS Mets at DX. Tumor multiplicity, in contrast, will present with anatomically separate, multiple tumors of different sizes arising independently in the GI tract. This form of tumor multiplicity usually will be seen in patients with neurofibromatosis type 1 or familial GIST syndrome, but in rare instances may be seen in patients without these conditions. This form of multiplicity should not be coded as metastasis, but the presence of multiple tumors should be coded in CS Site-Specific Factor 10, Tumor Multiplicity. When a solitary omental or mesenteric tumor mass is found with a primary GIST elsewhere, do not code this as a metastasis. Code it as multiple tumors in CS Site-Specific Factor 10, Tumor Multiplicity. When multiple tumor areas are present and it is not stated whether these are metastases or independent tumors, consult with a physician if possible to determine how to code them. If a decision cannot be made, code as 99.
Code Description AJCC 7 M AJCC 6 M Summary Stage 1977 M Summary Stage 2000 M
00 No distant metastasis M0 NA NONE NONE
10 Distant lymph node(s), including:
For all subsites:
Mesenteric, NOS:
Inferior mesenteric
Superior mesenteric
Para-aortic
Porta hepatis (portal) (hilar) (in hilus of liver)
Retropancreatic
Retroperitoneal
For all subsites EXCEPT lesser curvature :
Hepatoduodenal
Distant lymph nodes, NOS
M1 NA D D
40 Distant metastasis(es) except distant lymph node(s) including:
Peritoneal nodules
Liver parenchymal nodules
Carcinomatosis
Malignant peritoneal cytology
M1 NA D D
50 40 + 10

Distant metastasis plus distant lymph nodes
M1 NA D D
60 Distant metastasis, NOS

Stated as M1 with no other information on distant metastasis
M1 NA D D
99 Unknown; distant metastasis not stated
Distant metastasis cannot be assessed
Not documented in patient record
M0 NA U U