MP/H rules/Histology--Breast: How many primaries and what histologies are coded for a left breast when a bi-lumpectomy path reveals one tumor with a microscopic focus of mucinous adenocarcinoma and extensive DCIS and a second .9 cm mucinous adenocarcinoma with extensive DCIS, and the subsequent mastectomy reveals foci of residual DCIS and Paget's disease of the nipple?
For cases diagnosed 2007 or later:
There are two primaries. Primary 1: The two tumors described on the pathology report from the lumpectomy are a single primary using rule M13. Primary 2: Disregard the foci of residual DCIS. Paget disease of the nipple is a separate primary using rule M12.
Primary 1: invasive mucinous adenocarcinoma and extensive ductal carcinoma in situ: Code the histology as 8480/3 [mucinous adenocarcinoma] using rule H27.
Primary 2: Paget disease of nipple: Code the histology as 8540/3 [Paget disease] using rule H14.
EOD-Extension/EOD-Lymph Nodes--Bladder: Are "perivesical nodules" coded in the EOD-Lymph Nodes field or are they discontinuous extension and coded in the EOD-Extension field?
For cases diagnosed 1998-2003:
Code "perivesical nodules" in the EOD-Lymph Nodes field as involvement of regional lymph nodes. Each gross nodule of metastatic carcinoma in the fat surrounding an organ is counted as one positive regional lymph node.
EOD 2018/EOD Regional Nodes--Oropharynx: Is code 550 missing “< equal to 6 cm” in the data item EOD Regional Nodes for Oropharynx HPV-Associated, Version 9? Otherwise, bilateral or contralateral lymph nodes with extranodal extension (ENE) that are >6 cm could fit into 550 OR 650.
Code 550 is missing “< equal to 6 cm.” In addition, code 650 should include ipsilateral lymph nodes as well.
Revised codes:
Code 550
CLINICAL ASSESSMENT only
Bilateral or contralateral lymph nodes, < equal to 6 cm WITH clinical evidence of ENE
Code 650
CLINICAL ASSESSMENT only
Ipsilateral, Bilateral or Contralateral lymph nodes > 6 cm WITH or WITHOUT clinical evidence of ENE
These changes will be implemented in Version 3.4 (October 2026). We apologize for the error.
Histology (Pre-2007): What code is used to represent the histology "poorly differentiated invasive transitional cell carcinoma with extensive squamous and focal glandular differentiation"?
For tumors diagnosed prior to 2007:
Code the Histology field to 8120/33 [transitional cell carcinoma, NOS, poorly differentiated]. The ICD-O-3 does not have a separate code for transitional cell carcinoma with squamous and/or glandular differentiation.
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.
Grade/Sarcoma--Breast: Is the correct grade for high grade angiosarcoma of the breast a code 3 or 4? The breast usually uses a three grade system but sarcoma is not a typical histologic type of the breast.
Assign grade code 4 using the sarcoma table. Nottingham or Bloom-Richardson (BR) Score/Grade does not apply to angiosarcomas. This is a good question and points out needed clarification of the grade rules.
Primary Site--Esophagus: What is the difference between C15.5 [Lower third of esophagus] and C15.2 [Abdominal esophagus]?
These descriptions represent the use of two different ways the esophagus can be divided anatomically. The two different systems used are illustrated in the SEER Self Instruction Manual for Tumor Registrars: Book 4. Assign the primary site code that describes the location of the tumor in the same way the tumor's location is described in the medical record.
Histology (Pre-2007): What code is used to represent the histology if the final diagnosis between an electron microscopy report and the immunocytochemistry (ICC) differs and both histologies are specific (e.g., one report states papillary carcinoma and the other states squamous cell carcinoma)?
For tumors diagnosed prior to 2007:
There is no established hierarchy between electron microscopy and ICC findings. Contact the pathologists involved in these types of cases to determine the final histologic diagnosis.
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.
Histology (Pre-2007)--Breast: What code is used to represent the histology for a single lesion with "metaplastic carcinoma" and the majority of tumor has sarcomatoid appearance? Squamous cell carcinoma and high grade intraductal carcinoma are also present. Is the term "sarcomatoid" equivalent to sarcoma?
For tumors diagnosed prior to 2007:
For cases diagnosed on or after 1/1/2001: Code the Histology field to 8575/3 [metaplastic carcinoma]. Sarcomatoid is not coded as sarcoma.
The terms metaplastic carcinoma, squamous cell carcinoma and intraductal carcinoma are used, but only the metaplastic and squamous cell carcinomas are invasive. Metaplastic, loosely defined, means tissue that is not normal.
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.
Reportability/Histology--Gallbladder: Is Intracholecystic papillary neoplasm (ICPN) with low-grade intraepithelial neoplasia reportable? The primary site is gallbladder.
Intracholecystic papillary neoplasm (ICPN) with low-grade intraepithelial neoplasia is not reportable. The WHO assigns a behavior of 0 to these neoplasms.
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