Primary Site/Sarcoma--Breast: Is the primary site coded to C504 [upper-outer quadrant of breast] or C493 [ Connective, subcutaneous and other soft tissue of thorax ] for a tumor described as a "high grade soft tissue sarcoma present in the upper outer quadrant of breast"?
If the sarcoma is primary in the breast, code the primary site to C504 [upper-outer quadrant of breast]. C500 - C509 includes soft tissue of breast.
Diagnostic Confirmation--Leukemia: How is this field coded when the clinician confirms that the diagnosis of CML is based on a combination of the clinical picture and positive cytogenetic studies?
Assign code 1 [Positive histology]. For leukemia only, assign code 1 for positive hematologic findings including peripheral blood smears, CBCs and WBCs.
Cytogenetics studies would have been done on blood. Therefore, histology provided diagnostic confirmation as it would with smear, bone marrow, or other special study of blood cells.
Histology: What is the histology code for a soft tissue thigh mass that was diagnosed as Ewing sarcoma/PNET, primitive neuroectodermal tumor?
The histologies stated for this case are Ewing sarcoma (9260) and PNET, primitive neuroectodermal tumor,(9364)*. Use the Other Site Rules, starting with H8. Stop at H17 and assign the higher histology code -- 9364/3 [Peripheral neuroectodermal tumor].
*The term "PNET" is used for two different tumors. One is primitive neuroectodermal tumor (9473) and pertains to brain tumors per ICD-O-3 review. The other is peripheral primitive neuroectodermal tumor (pNET or PPNET 9364) and pertains to bone or soft tissue tumors. This case is stated to be soft tissue and Ewing sarcoma, so it is 9364 rather than 9473.
MP/H Rules/Multiple primaries--Colon: Does rule M7 apply here (A frank malignant or in situ adenocarcinoma and an in situ or malignant tumor in a polyp are a single primary)? Can the frank malignant adenocarcinoma be any specific type of adenocarcinoma for this rule to apply?
A patient has 2 synchronous tumors in the ascending colon. The first is grade 3 adenocarcinoma with signet ring differentiation and focal mucinous features (8255/3). The second is grade 2-3 adenocarcinoma in a tubulovillous adenoma (8263/3).
M7 applies to this case. The frank adenocarcinoma can be a specific type of adenocarcinoma.
Reportability--Skin: Is a pilomatrix carcinoma of the skin reportable if it is described as being a malignant diagnosis based on poor circumscription, infiltrative growth pattern, and focal abundant mitoses?
UPDATED June 2026
Pilomatrix carcinoma is not reportable to SEER. Skin primaries with histology codes from 8090 to 8110 are not reportable. Pilomatrix carcinoma is coded 8110/3.
See the SEER Coding Manual under Reportability, 1b: "Do not report (Exceptions to reporting requirements)"
Place of Birth: When there is conflicting information, which record takes precedence in coding this field, the medical record or the death certificate?
If there is a discrepancy, use the information from the medical record to code the Place of Birth field. The information from the medical record is provided by the patient, the information on the death certificate is provided by others. If the medical record does not contain birth information, use the information from the death certificate.
Date of Diagnosis: How do you code this field when the pathologic confirmation is delayed for 2 months because the clinician decides to "watch and see what happens" to a CT identified mass thought to be either a "metastasis from a previously diagnosed malignancy or a new primary"?
Code the Date of Diagnosis field to the date of the scan. This is the earliest date that a recognized medical practitioner said the patient had cancer. The diagnosis on the CT scan was a malignancy. The only question was whether the mass on the scan was metastatic or a primary.
Grade, Differentiation--All Sites: What code is used to represent this field when a pathology report describes a tumor as a low grade neoplasm consistent with a specific histologic type (e.g., Low grade neoplasm consistent with carcinoid)?
Code the Grade, Differentiation field to 2 [Low grade].
EOD-Extension--Ovary: What code is used to represent this field for an ovarian primary presenting with "spread to the omentum"?
For cases diagnosed 1998-2003:
Code the EOD-Extension field to 75 [Peritoneal implants, NOS] because the size of the implants on the omentum is not known.
Note 6 was added to the EOD scheme which states that both direct extension and discontinuous metastasis to the omentum are coded in the range 70-75 depending on how the peritoneal implants are described.
Histology (Pre-2007)--Skin: Are "atypical melanocytic hyperplasia" and "severe melanotic dysplasia" synonyms for melanoma in situ?
For tumors diagnosed prior to 2007:
No. SEER determines its reportable list from the ICD-O-3. The above terms are listed as tumor-like lesions and conditions, but are not in situ or malignant.
For tumors diagnosed 2007 or later, refer to the MP/H rules. If there are still questions about how this type of tumor should be coded, submit a new question to SINQ and include the difficulties you are encountering in applying the MP/H rules.
An official website of the United States government
Home