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Report Produced: 03/26/2023 07:40 AM

Report Question ID Question Discussion Answer (Descending)
20081117 Histology--Brain and CNS: How is histology to be coded for a pituicytoma WHO grade I, of the pituitary?

Assign code 9380/1 [glioma, borderline].

According to our pathologist consultant, the term pituicytoma is restricted to low-grade glial neoplasms of the neurohypophysis or infundibulum. The best category currently available for these is glioma.


Solid Tumor Rules (2018)/Histology--Corpus uteri: What is the correct histology code for "Mesophrenic-like adenocarcinoma" of the corpus uteri?" See Discussion.

The article I read ( makes the distinction between mesophrenic adenocarcinoma and mesophrenic-like adenocarcinoma. The authors propose the term mesonephric-like Mullerian adenocarcinoma. So would this be coded as Mullerian adenocarcinoma?

Assign code 9110/3, mesonephric adenocarcinoma. These tumors commonly arise in the cervical wall and more commonly involve the lower uterine segment than do other cervical adenocarcinomas.


Solid Tumor Rules 2018/Histology--Testis: What is the histology code for a 2018 diagnosis of left testis tumor diagnosed as mixed germ cell tumor with secondary malignant components: primitive neuroectodermal tumor (PNET) and rhabdomyosarcoma? See Discussion.

The patient has testicular cancer with bilateral lung metastases and possible liver metastasis. The left orchiectomy final diagnosis was The Summary describes a single tumor that is, Germ cell neoplasia in situ (GCNIS) is also present. Although there is mixed germ cell tumor present, the PNET component of the tumor is locally invasive extending into the epididymis, hilar soft tissues, spermatic cord, and tunica vaginalis. The mixed germ cell tumor is limited to the testis only.

We are instructed not to use to the term to code histology in the MP/H Rules General Instructions (Other Site Rules not updated for 2018), however the PNET comprises the majority of this tumor and represents the most extensive disease. Should the PNET histology be ignored in this case as its a ?

Assign code 9084/3. According to our expert pathologist consultant, this is a teratoma with a somatic-type malignancy. This code is the best choice even though it does not capture the mixed germ cell elements of the tumor, or the character of the somatic component (rhadomyosarcoma, PNET).There aren't enough histology code numbers to cover all of the possibilities. Use text fields to describe the specifics of this case.


MP/H Rules/Histology--Sarcoma: What would be the morphology code for a low grade myofibroblastic sarcoma of the left distal forearm? I tried several different combinations but the closest I could come up with is myosarcoma.

Assign code 8825/3. Apply the ICD-O-3 Matrix Concept, Rule F, page 29 of the hardcover ICD-O-3. The WHO Classification of Soft tissue and Bone, page 85, lists low grade myofibroblastic sarcoma, also called myofibrosarcoma, 8825/3.


MP/H Rules/Histology--Head & Neck: How is the histology coded for a mammary analogue secretory carcinoma (MASC) of the parotid gland? See Discussion.

There is no histology listed in the ICD-O-3 for a mammary analogue secretory carcinoma. The pathologist stated that, "MASC is a recently described salivary gland tumor type which, as the name implies, resembles secretory carcinoma of the breast." Should the histology be coded 8550/3 [acinar carcinoma] or 8502/3 [secretory carcinoma of breast]?

Assign code 8502/3 [secretory carcinoma of breast].

Acinar carcinoma [8550/3] describes a very typical type of salivary gland tumor only. This histology code does not adequately capture the histology in this case which describes a secretory carcinoma that is similar to mammary cancer. Both of these elements are reflected in the histology code 8502/3 [secretory carcinoma of breast].


Histology--Corpus uteri: Is 8020/3 used for a predominantly dedifferentiated carcinoma with focal well-differentiated endometrioid adenocarcinoma diagnosed in 2018? See Discussion.

After a little research, it appears as though Endometrial Dedifferentiated carcinoma is a relatively new term and is set to be included in ICD-O-3.2:

If you look at the link on that page for All Additions, Changes, and Revisions to the ICD-O-3, 1st Revision for ICDO-3.2, there is 8020/3 Dedifferentiated carcinoma. Currently, 8020/3 is Carcinoma, undifferentiated, NOS. For 2018 diagnosis, would you use 8020/3 for a predominantly dedifferentiated carcinoma with focal well-differentiated endometrioid adenocarcinoma as stated in the pathology: Uterus, bilateral ovaries and fallopian tubes; supracervical hysterectomy/BSO: Predominantly dedifferentiated carcinoma with focal well-differentiated endometrioid adenocarcinoma in the endometrium, FIGO grade 1 Portion of omentum, omental/anterior abdominal wall/ round ligament/uterine/small bowel mesenteric tumor nodules all involved by dedifferentiated carcinoma. Synoptic reads as follows: Histological Type: Endometrioid carcinoma, NOS Dedifferentiated carcinoma predominantly Histological Grade: Endometrioid carcinoma, FIGO grade 1.

Assign code 8380/3 for endometrioid carcinoma, NOS as this is listed as the histological type in the synoptic report.

20021025 Histology: What code is used to represent the histology "endometrioid adenocarcinoma, villoglandular type"?

Assign code 8262/3 [Villous adenocarcinoma].

According to the WHO Classification of Tumours, Breast and Female Genital Organs (2003), villoglandular is one of four variants of endometroid adenocarcinoma. The corresponding ICD-O-3 code according to WHO is 8262/3.


MP/H Rules/Histology--Thyroid: What is the correct histology when final diagnosis of a thyroidectomy includes the descriptor "papillary and follicular architecture?" See Discussion.

Total thyroidectomy Final Diagnosis: Papillary carcinoma, classical type, with papillary and follicular architecture.

The 2007 MP/H rules state that the term architecture is reserved for coding subtype of in situ primaries only. However, SINQ 20130165 appears to indicate this should be coded for invasive thyroid subtypes as well. Can you confirm the addition of the term architecture for determining an invasive histologic subtype for thyroid?

Assign code 8260/3, papillary carcinoma per Multiple Primaries/Histology Rule H14.

Architecture is reserved for coding subtype of in situ primaries only. SINQ 20130165 is not intended to indicate this should be coded for invasive thyroid subtypes.


MP/H Rules/Histology--Thyroid: How should histology be coded for a thyroidectomy final diagnosis of papillary thyroid carcinoma, favor cribriform-morula variant? See Discussion.

This specific histology (cribriform-morula variant of papillary thyroid carcinoma) is not found in the ICD-O and is not mentioned in the 2007 MP/H Manual. However, per a web search it appears that this is a distinct type of papillary thyroid carcinoma (

Example: Right lobectomy shows thyroid epithelial neoplasm, pending consultation.

Consultation: Thyroid gland, right lobe: papillary thyroid carcinoma, favor cribriform-morula variant.

Consultation Comment: IHC stains argue against medullary carcinoma. The histologic features of growth patterns and cytologic atypia (with rare grooves and pseudoinclusions) and the immunohistochemical profile support a diagnosis of papillary thyroid carcinoma, favoring the cribriform-morula variant. It is important to note that a significant number of patients with this variant of papillary thyroid carcinoma have been associated with familial adenomatous polyposis syndrome.

Assign code 8260/3 for papillary carcinoma of thyroid. Cribriform-morula variant is not listed in ICD-O-3 for papillary carcinoma. Multiple Primaries/Histology Rule H14 states to code papillary carcinoma of the thyroid to papillary adenocarcinoma, NOS (8260).


Solid Tumor Rules (2018/2021)/Histology--Breast:  How is histology coded for a diagnosis of invasive mammary neuroendocrine tumor (NET), grade 2/3? See Discussion.

Table 3 (Breast Equivalent Terms and Definitions) lists “Neuroendocrine tumor, well-differentiated” of the breast as histology 8246/3. There is no entry for a grade 2 neuroendocrine tumor of the breast in Table 3.  

The pathologist did not indicate the neuroendocrine tumor was poorly differentiated (or it would otherwise be a small cell carcinoma). The pathologist noted “By current WHO criteria, this tumor is characteristic of a mammary neuroendocrine tumor, grade 2.  These invasive tumors have similar prognostic and predictive features of invasive ductal carcinoma of the same grade and stage.”

Assign code 8249/3, neuroendocrine tumor, grade 2 based on the pathologist statement of mammary neuroendocrine tumor grade 2.  According to WHO Classification of Tumors of the Breast, 5th edition, neuroendocrine tumor (NET) is an invasive tumor characterized by low/intermediate grade.

If the histology term is not listed in the Solid Tumor rules, the instructions state to also check ICD-O and updates. Per ICD-O, NET, grade 2 is coded 8249/3. Breast Table 3 will be updated for 2023.