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Report Produced: 02/27/2026 02:05 AM

Report Question ID Question Discussion Answer Year
20150023

MP/H Rules/Histology--Thyroid: When is 8341/3, papillary microcarcinoma coded? The code description in ICD-O-3 is followed by (C739), yet there are two SINQ answers that tell us specifically to not use this code for thyroid primaries. Even the first revision of ICD-O-3 still carries the (C739) as part of this code, which goes against SINQ 20110027 and 20081127.

Per the WHO Tumors of Endocrine Organs, for thyroid primaries/cancer only, the term micropapillary does not refer to a specific histologic type. It means that the papillary portion of the tumor is minimal or occult (1cm or less in diameter) and was found incidentally. WHO does not recognize the code 8341 and classifies papillary microcarcinoma of the thyroid as a variant of papillary thyroid and thereby should be coded to 8260. If the primary is thyroid and the pathology states papillary microcarcinoma or micropapillary carcinoma, code 8260 is correct. This information will be included in the upcoming revisions to the MP/H manual.                        

2015
20150019

Reportability/Histology--Pancreas:  Is well-differentiated neuroendocrine tumor (M8240/3) as stated on a pathology report reportable or can the clinical information be used as an adjunct to the path report, which further states the specific type of neuroendocrine tumor is an Insulinoma, therefore, NOT reportable (M8151/0)? See discussion.

The diagnosis date is 2/24/14.  The pathology report of the pancreas shows: Well-differentiated neuroendocrine tumor (NET), low grade (WHO G1 of 3). Addendum: Ki-67 confirms low grade of pancreatic endocrine tumor (less than 2% Ki-67/MIB-1 index). Chromogranin confirms the endocrine nature of the tumor. The Pre and Post Op Diagnosis is pancreatic neuroendocrine tumor consistent with insulinoma. AJCC Stage as noted on path report: pT1, pNX, pM.

The physician states: The patient has a well-documented insulinoma. Biochemistries confirmed the disease and it is localized in the tail of the pancreas.

The issue with NETs is that pathology report reflects what is seen or what is quantified under the microscope; often, there is a specimen without the accompanying medical history and clinical signs. Many of these NETs are specified on the basis of the hormone, as usually measured in the blood, that is overproduced, something not seen microscopically. All of the islet cell tumors are NETs. The insulinoma in the example above is a well-differentiated NET that is causing insulin to be over-produced. Thus, the diagnoses are not discordant; insulinoma is a more specific NET.

When the pathology diagnosis is a neuroendocrine tumor (/3) and the clinical diagnosis is an insulinoma (/0), report the case.  Although ICD-O-3 classifies insulinoma as /0, the most recent WHO classification lists it as /3. The pathologist and physicians for this case are likely guided by the WHO classification and as a result, would view both the NET diagnosis and the insulinoma diagnosis as malignant. You could report this case as 8240/3 or 8151/3.

2015
20150038

Reportability/MP/H Rules/Histology: Is malignant perivascular epithelioid cell tumor (PEComa) reportable, and if so, what is the histology code?

Malignant perivascular epithelioid cell tumor (PEComa) is reportable because it is malignant. Assign 8005/3 to malignant PEComa.

We consulted an ICD-O-3 expert who explained that some PEComas such as angiomyolipoma and lymphangiomyomatosis have specific ICD-O codes and their malignant counterparts may be coded to 8860/3 and 9174/3 respectively. There are no separate ICD-O codes for other specific PEComas, e.g., clear cell “sugar” tumor of lung, clear cell myomelanocytic tumor of the falciform ligament and some “unusual” clear cell tumors occurring in other organs—or for PEComa, NOS. These PEComas may therefore be coded to 8005 as clear cell tumors NOS; in other words as clear cell tumors that are not clear cell variants of carcinomas, sarcomas, or other specific tumor type.

Please note, PEComa is non-specific as to behavior. Unless the pathologist states that it is malignant, (as was the case for this question), the default code is 8005/1 (non-reportable).

2015
20150021

MP/H Rules/Histology--Skin: How is histology coded for an "endocrine mucin-producing sweat gland carcinoma with transformation to mucinous carcinoma"? See Discussion.

Endocrine mucin-producing sweat gland carcinoma (EMPSCG) is a rare type of low-grade sweat gland carcinoma. Some journal articles indicate that most patients with EMPSCG have coexisting mucinous carcinomas, suggesting that EMPSCG is a precursor to invasive mucinous carcinoma of the skin. Sweat gland carcinoma has its own histology code per the ICD-O-3 (8400/3); should an endocrine mucin-producing sweat gland carcinoma also be coded as 8400/3? If so, would the correct histology for the skin case above be mucinous carcinoma (8480/3) per Rule H17? Conversely, if the terms "mucin-producing" are referring to mucin-producing carcinoma, and not referring to the sweat gland carcinoma, would the histology be coded 8481/3 (mucin-producing carcinoma)?

Assign 8480/3.

There is no mixed ICD-O-3 code for EMPSCG. Both histologies are in the mucinous family: mucinous adenocarcinoma (8480/3) and sweat gland carcinoma (8400/3). Apply Other sites rule H17 and code the numerically higher ICD-O-3 code (8480/3).

Endocrine mucin-producing sweat gland carcinoma (EMPSGC) is a rare low-grade sweat gland carcinoma with a strong predilection to the eyelid region. It is histologically analogous to endocrine ductal carcinoma/solid papillary carcinoma of the breast and is characterized by a multinodular solid cystic mucinous tumor with immunoreactivity to neuroendocrine markers. Only 20 cases of this unusual tumor have been reported.

2015
20150046

Reportability--Appendix:  Is the appendix the primary site for a low grade mucinous appendiceal neoplasm (LAMN) with diffuse peritoneal dissemination?  See discussion.

Patient had an appendectomy revealing a low grade mucinous appendiceal neoplasm (LAMN) with diffuse peritoneal dissemination. Patient now with cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC), which revealed metastatic disease in the abdomen, omentum, pelvic peritoneum, peri-cecal, and gallbladder.

For cases diagnosed prior to 1/1/2022

Low-grade appendiceal mucinous neoplasm (LAMN) is not reportable, even when it spreads within the peritoneal cavity, according to our expert pathologist consultant. Peritoneal spread of this /1 neoplasm does not indicate malignancy. It is still /1 when there is spread of LAMN in the peritoneal cavity.

 2015
20150041

MP/H Rules/Multiple primaries--Breast: Does rule M10 apply in this situation?

L breast biopsy = INVASIVE DUCTAL CARCINOMA

L breast simple mastectomy = 2.0 cm INVASIVE DUCTAL CARCINOMA with an incidental finding of separate 1.0 cm INVASIVE LOBULAR CARCINOMA; pathologist specifically states the tumors are morphologically different. The tumors are both pure Ductal/pure Lobular.

Yes, Breast rule M10 applies. This case is a single primary.

Follow the MP/H rules even though the "pathologist specifically states the tumors are morphologically different" so that situations like this are reported consistenty accross cancer registries, regions, and states for consistent national reporting.

2015
20150031

MP/H Rules/Multiple primaries--Colon: This is an unusual case of multifocal colon cancer. The case is staged pT4b,N1b. Per our MP rules, this will be 4 separate primaries. Would this be an exception to the rules; if not now, possibly in future versions of the MP rules for colon cancer? See discussion.

The path report reads: COMMENT: There is multifocal involvement throughout both bowel segments which combined represent a subtotal colectomy procedure. There are at least 11 tumors, all of which are histologically similar. Given the unusual gross appearance, a representative portion of the largest mass (hepatic flexure) was forwarded to _____ for flow cytometric evaluation. There is chronic active colitis in the background suggestive of idiopathic inflammatory bowel disease, specifically ulcerative colitis. However, no dysplasia is seen in multiple random sections of grossly benign large bowel. ADDENDUM from expert gastroenterologist: The carcinomas are poorly differentiated without specific histologic features but are consistent with colon primaries. These findings are consistent with an MLH1-deficient carcinoma. Given the background chronic active colitis consistent with ulcerative colitis, this likely represents colitis-associated neoplasia which can be associated with multifocality.

This unusual case of multifocal colon cancer is not an exception to the MP/H rules currently.

The current WHO classification for colon tumors mentions ulcerative colitis (UC) associated colorectal cancers and states they are often multiple. This will be discussed for the next version of the MP/H rules.

2015
20150051

Reportability--Brain and CNS: Is schwannoma of the extracranial part of a cranial nerve reportable? Some cranial nerves, like facial nerve, have intracranial and extracranial branches.

An extracranial schwannoma is not reportable. The schwannoma must arise on the intracranial part of the nerve to be reportable.

2015
20150009

Multiple Primaries/Behavior--Lung: When a patient has an invasive lung primary, how do in situ tumors of the lung affect the determination of multiple primaries? See discussion.

How many primaries should be reported when a 12/19/14 RUL lung wedge resection shows: 2.0 cm invasive adenocarcinoma (8140/3) and an additional RUL wedge resection during the same procedure shows: multifocal adenocarcinoma in situ (bronchioloalveolar carcinoma), non-mucinous type (8252/2) size: 1 mm – 2 mm; followed by a 2/12/15 left upper lobectomy also showing Adenocarcinoma, invasive at several foci, with a prominent bronchioloalveolar (in situ) component….tumor focality: multifocal (10 cm mass, 6 cm mass and numerous smaller foci)?

Most often when the invasive tumor and the in situ component are in the same lung and are the same histology, rule M12 (example 3) applies and this is a single primary. If the first wedge resection included part of the tumor and the in situ was not separate from the tumor, it is a single primary. We suspect that the margins were positive on the first wedge specimen which prompted the second wedge resection where the in situ was found. In addition, terminology for lung malignancies is undergoing change: what was called BAC (invasive) is now called adenocarcinoma in situ.

 2015
20150066

Grade--Breast: Do you take grade from the most representative specimen along with the histology? What is the correct histology/grade combination? See discussion.

 

Breast biopsy (from hospital A): DCIS, solid, cribriform, comedo type, high nuclear grade

Breast Lumpectomy (from hospital B): DCIS, cribriform type, nuclear grade 1, tumor 2.5cm

Assign 8201/2 for this case.

MP/H rules are to code histology based on the specimen with the most tumor tissue. That would be the lumpectomy in this case. The histology is DCIS, cribriform type.

Reference: http://seer.cancer.gov/tools/mphrules/mphrules_instructions.pdf

The general rule for grade is to code the highest grade specified within the applicable grading system. For the case information provided, follow instruction #5, nuclear grade: use Coding for Solid Tumors #7: 2-, 3-, or 4- grade system. High nuclear grade (grade code 3 for breast) is higher than nuclear grade 1 (grade code 1).

Reference: http://seer.cancer.gov/tools/grade/

2015