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Produced: 01/14/2025 7:22 AM
Question 20120024
Inquiry Details
References:
2007 MP/H Rules
Question:
MP/H Rules/Histology--Breast: How many primaries are abstracted and what histology codes are used when a patient has two tumors, one reported as duct and lobular carcinoma and another reported as pleomorphic lobular and duct carcinoma? See Discussion.
Discussion:
The pathology report indicated two tumors in the upper outer quadrant of the breast. One tumor has duct and lobular carcinoma and the other tumor has pleomorphic lobular and duct carcinoma. Per a web search, pleomorphic lobular carcinoma is a recently recognized subtype of lobular cancer.
According to the MP/H Rules, Breast Equivalent Terms, Definitions, Tables and Illustrations, "pleomorphic carcinoma" is a specific type of duct carcinoma [8022/3]. This is not listed as a combined histology in Table 3. Should this be abstracted as a single primary per Rule M10, with the histology coded 8523/3 [infiltrating duct mixed with other types of carcinoma]? Or should this be abstracted as two primaries per Rule M12, with the histologies coded as 8022/3 [pleomorphic carcinoma] and 8522/3 [infiltrating duct and infiltrating lobular carcinoma]?
Answer:
This is a single primary with the histology coded as infiltrating duct and infiltrating lobular carcinoma [8522/3].
For cases diagnosed 2007 or later, the steps used to arrive at this decision are:
Open the Multiple Primary and Histology Coding Rules manual. For a breast primary, start with the Breast Multiple Primary Rules because there are site specific rules for breast primaries.
Start at Rule M4 because this patient has multiple tumors in the same breast. The rules are intended to be reviewed in consecutive order within the applicable Module. Abstract a single primary as tumors that are lobular [8520] and intraductal or duct are a single primary.
Use the Breast Histology Coding Rules to determine the correct histology for these multiple tumors abstracted as a single primary. Start at Rule H20 as there were multiple tumors present but it is a single primary. Code the histology to 8522 [duct and lobular] when there is any combination of lobular [8520] and duct carcinoma.
The Note for Rule M10 indicates Table 1 and Table 2 are used to identify specific intraductal and duct carcinomas. Referring to Table 2 (Duct 8500/3 and Specific Duct Carcinomas) note that pleomorphic carcinoma is listed as a specific type of duct carcinoma. Pleomorphic is a word that describes the cellular appearance rather than a specific histology. It is coded when that is the only description/diagnosis given (pleomorphic carcinoma/pleomorphic duct carcinoma). In this case, both duct and lobular are describing the actual histologic types. Ignore the term "pleomorphic" and code the actual histologic descriptors, ductal and lobular. We will make appropriate changes to the breast rules in the MP/H revisions so this distinction is clear.
