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Report Produced: 01/26/2023 20:33 PM

Report Question ID Question (Descending) Discussion Answer

MP/H Rules/Histology--Breast: What is the histology code for the following?

4/21/03 Left breast: infiltrating ductal carcinoma, grade 3 micropapillary type. Tumor size: 3.5 cms; deep margin negative. Skin, nipple & areola positive for invasive ductal carcinoma. Dermal lymphatic invasion by carcinoma breast. Extensive intraductal component absent. 6+/6. See Discussion.

How should histology be coded for a 2003 diagnosis and also for the same diagnosis in 2007 or later?

For a case diagnosed in 2003, code 8507/3 [Duct micropapillary carcinoma]. See Coding Complex Morphologic Diagnoses, revised August 2002, 3rd example on page 5 and page 3, #4.

For cases diagnosed 2007 or later, code 8507/3 [Duct micropapillary carcinoma]. Use rule H12.


MP/H Rules/Histology--Breast: What is the histology code for "invasive carcinoma of the breast, no special type" as the final diagnosis on a pathology report? See Discussion.

Recently pathology reports for breast primaries are no longer listing invasive ductal carcinoma as the histology on many cases if the treating physician calls the cancer an invasive ductal carcinoma. The pathology report (final diagnosis and synopsis) state this is invasive carcinoma, no special type.

Upon inquiry to the pathology department, the response received stated, In 2012, the WHO got rid of ductal carcinoma as a specific type. So what would have been called Invasive ductal carcinoma, Not Otherwise Specified (NOS), is now being called Invasive carcinoma, No Special Type (NST). In the new WHO classification, lobular, tubular, cribriform, mucinous, etc. are the special types. But ductal is gone.

Is this a change in terminology? Should these cases be coded as 8500/3 [ductal carcinoma, NOS] or 8010/3 [carcinoma, NOS]?

Code the histology to ductal carcinoma, NOS [8500/3] for a pathology report with a final diagnosis of "invasive carcinoma, no special type." Do not code the histology to carcinoma, NOS [8010/3].

The 4th Edition of the WHO Classification of Tumors of the Breast refers to invasive ductal carcinoma as invasive carcinoma, no special type. The ICD-O-3 code remains the same as invasive duct carcinoma [8500/3]. The next revision to the MP/H Solid Tumor Rules will clarify this issue.


MP/H Rules/Histology--Breast: What is the correct histology code and MP/H rule used for 1) infiltrating ductal carcinoma, mucinous type and 2) infiltrating ductal carcinoma with features of tubular carcinoma? See Discussion.

There is confusion as to which rule applies. Should the histologies be coded to 8480/3 [mucinous adenocarcinoma] and 8211/3 [tubular adenocarcinoma] respectively per rule H12? Rule H12 states to code the most specific histologic term; "type" and "with features of" are used in the pathologic diagnosis and are both terms that can be used to code the specific histology. Or would the histology be coded 8523 for both examples per rule H17 because neither histologic codes 8480/3 or 8211/3 are included as examples of duct carcinomas, nor are they included in Table 2?

For cases diagnosed 2007 or later, code 8523 [infiltrating duct mixed with other types of carcinoma] for

1. Infiltrating ductal carcinoma, mucinous type and

2. Infiltrating ductal carcinoma with features of tubular carcinoma

The infiltrating ductal types in Rule H12 are listed (8022, 8035, 8501-8508) and do not include mucinous or tubular. We cannot use this rule. The first rule that applies to these single tumors is H17, code to 8523. If you look up 8523 in the numerical morphology section of ICD-O-3, you will see similar examples included in the definition of this code.


MP/H Rules/Histology--Breast: What histology code(s) and MP/H rule applies for a breast resection final diagnosis of "undifferentiated sarcoma associated with a malignant phyllodes tumor and a tumor size of approximately 7 x 6.5 x 4 cm"? (The tumor is primarily sarcoma, with the phyllodes tumor measuring 2.8 cm)? See Discussion.

Patient has a diagnosis of undifferentiated sarcoma with an associated malignant phyllodes tumor in a single mass. Should this be abstracted as two primaries, one for an undifferentiated sarcoma and the other for a malignant phyllodes tumor? Which MP/H rule applies?

Abstract a single primary. Based on the information provided, this is a single tumor, and therefore a single primary, Rule M3. Code the histology to malignant phyllodes tumor.

According to our expert pathologist consultant, "The presence of a phyllodes tumor component identifies the whole thing as such. Stromal overgrowth/sarcoma is the usual identifier of malignancy in a phyllodes tumor. (If there were no phyllodes component we would be left with undifferentiated sarcoma, but that is not the case here. The diagnosis of malignancy in phyllodes tumor may be difficult/problematic when there is no overt stromal/sarcoma overgrowth as in this case.) As an aside, the behaviors of pure sarcoma and a phyllodes tumor such as we have here are similar, but we would lose the primary diagnosis if we just called this sarcoma."


MP/H Rules/Histology--Breast: What histology code and MP/H Rule applies to the Histologic Type of "invasive ductal carcinoma with metaplastic stroma" for a single breast tumor? See Discussion.

The patient had a partial mastectomy with final diagnosis of invasive ductal carcinoma with metaplastic stroma. Knowing that metaplastic breast carcinoma has a worse prognosis than other types of breast cancer, is metaplastic stroma a synonym for metaplastic carcinoma when used in this context?

Code to metaplastic carcinoma, 8575/3. According to our expert pathologist consultant, "The term 'metaplastic stroma' implies that at least a portion of the carcinoma has undergone a 'metaplastic' change from epithelial in appearance to 'stromal' in appearance. I assume this is what CAP means by 'Invasive mammary carcinoma with matrix production,' which the WHO equates to metaplastic carcinoma."


MP/H Rules/Histology--Breast: Should encapsulated papillary carcinoma of the breast with a separate focus of ductal carcinoma in situ be coded as 8050/2 (papillary carcinoma) and staged as in situ? See Discussion.

Pathology--Right breast, lumpectomy with needle localization: Encapsulated papillary carcinoma of the breast. A separate focus of ductal carcinoma in situ is present. Sentinel lymph node, right breast, biopsy: One lymph node, negative for malignancy. No metastatic carcinoma is seen on slides stained with immunostain for cytokeratin (AE1/AE3). Specimen laterality: Right. Tumor size: 1.2 cm. Histologic type: Encapsulated papillary carcinoma. Nuclear grade: Grade 1 (low). Mitotic rate: Score 1. Ductal carcinoma in situ (DCIS): DCIS is present. Estimated size (extent) of DCIS: 3 mm. Architectural patterns: Cribriform and papillary. Nuclear grade: grade 1 (low). Necrosis: Not identified. Margins: Margins uninvolved by encapsulated papillary carcinoma. Distance from closest margin: 8 mm, superior Margins uninvolved by DCIS. Distance from closest margin: 11 mm, superior Lymph nodes: Total number of lymph nodes examined (sentinel and nonsentinel): 1. Number of sentinel lymph nodes examined: 1. Number of lymph nodes with tumor cells: 0. Pathologic staging: Primary tumor: See comment. Regional lymph nodes: pN0(i-). Comment: In the WHO Classification of Tumours of the Breast (2012), it is stated that "there is no universal agreement on how to stage encapsulated papillary carcinomas. In the absence of conventional invasive carcinoma, the consensus of the WHO Working Group was that such lesions should be staged and managed as Tis disease."

For cases diagnosed prior to 2018

Code as encapsulated papillary carcinoma, 8504/3; this is a synonym for intracystic carcinoma (WHO Classification of Tumors of the Breast). Stage this case as invasive.


MP/H Rules/Histology--Breast: How should histology be coded for a breast primary with resection final diagnosis of "Ductal carcinoma with neuroendocrine features?" See Discussion.

Should the histology for "Ductal carcinoma with neuroendocrine features" be coded to 8500 (Ductal carcinoma, NOS) or 8574 (Adenocarcinoma with neuroendocrine differentiation)?

Code the histology to 8574/3 for Ductal carcinoma with neuroendocrine features.

Ductal carcinoma is also called "invasive breast carcinoma of no special type." WHO classifies Invasive breast carcinoma with neuroendocrine differentiation as 8574/3.


MP/H Rules/Histology--Brain and CNS: What is the histology code for a tumor originating in the cerebellum and extending into the fourth venrticle described as a glioblastoma with primitive neuroectodermal tumor component (WHO Grade IV)?

The WHO Classification of CNS tumours lists glioblastoma with primitive neuroectodermal tumor component as a subtype of glioblastoma and assigns 9440/3. Also referred to as glioblastoma with a primitive neuronal component.


MP/H Rules/Histology--Brain and CNS: What is the histology code for a patient with a pathology report Final Diagnosis indicating, mucin-rich neuroepithelial neoplasm, favor low-grade? See Discussion.

The pathologist noted this was a challenging brain neoplasm that did not easily fit into a specific WHO diagnostic classification. Multiple differential diagnoses were given including pilomyxoid astrocytoma, ganglioglioma and dysembryoplastic neuroepithelial tumor (DNET), but there were no definitive features characteristic of any of these tumors. In the Comment section following the Final Diagnosis, it further states: "In summary, the tumor appears to be a difficult to classify non-infiltrating glial/glioneuronal neoplasm without definitive high-grade features."

Code as 9505/1, Ganglioglioma, NOS. The Multiple Primaries/Histology Rules for Benign and Borderline Intracranial and CNS Tumors Chart 1 lists several histology codes for neuronal and mixed neuronal-glial tumors. Ganglioglioma, formerly Glioneuroma that is now obstolete in ICD-O-3, is the most applicable in this situation.


MP/H Rules/Histology--Brain and CNS: What is the code for an embryonal tumor with multilayered rosettes. WHO shows the code as 9478/3, but this code is not available for use in the United States.

Assign ICD-O-3 code 9392/3 until code 9478/3 is implemented in 2018. Per our expert neuropathologist, embryonal tumor with multilayered rosettes was previously called ependymoblastoma.