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After consultation with our expert pathologist, the decision is report this case as a single primary. There was some confusion about how to apply the current MP/H rules to this pathology report given 1) the definition of M16 and M17 and 2) the likelihood for a single endometrial primary to present with several differentiations. According to our expert pathologist, "I would regard this case as a single endometrial primary with extensive endometrial involvement and several types of differentiation, all of which are seen in endometrial carcinomas."

Next, the Multiple Primary and Histology Coding Rules Manual is the correct source for coding histology for cases diagnosed 2007 or later.

The following steps are used to determine the histology code.

Open the Multiple Primary and Histology Coding Rules manual. For an endometrial primary, use the Other Sites Histo rules to determine the histology code because endometrium does not have site specific rules.

Start with the MULTIPLE TUMORS ABSTRACTED AS A SINGLE PRIMARY module, Rule H18. The rules are intended to be reviewed in consecutive order within the module from Rule H18 to Rule H31. You stop at the first rule that applies to the case you are processing.

Code the appropriate combination/mixed code (Table 2) when there are multiple specific histologies. GYN malignancies with multiple types of adenocarcinoma have histology coded to 8323/3 [mixed cell adenocarcinoma] per rule H30.

Always code primary site to the site of origin. Look for information about where the neoplasm originated. Primary site should always be coded to reflect the site of origin according to the medical opinion on the case. Always code the primary site based on where the tumor arose / site of origin. Site of origin may be indicated by terms such as "tumor arose from," "tumor originated in," or similar statements.

Refer to ICD-O-3.2 and ICD-O-3 for topographty codes that are associated with specific histologies whenthe medical documentation does not specify the primary site.

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

Angiocentric glioma is reportable. The best histology code currently available is 9380/1 [glioma, NOS; uncertain behavior].

According to the WHO Classification of Central Nervous System Tumours, Angiocentric glioma has a behavior of /1. WHO defines it as an epilepsy-associated stable or slowly growing cerebral tumour primarily affecting children and young adults; histopathologicaly characterized by an angiocentric pattern of growth, monomorphous bipolar cells and features of ependymal differentiation.

Answer revised 3/31/2022

Do not report cases based only on the TI-RADS category. The most recent information from ACR on TI-RADS indicates that neither TI-RADS 4 nor TI-RADS 5 is clearly defined as malignancy. TI-RADS 4 is "moderately suspicious" and TI-RADS 5 is "highly suspicious" but they do not specify what they are suspicious for. We need more information to determine reportability.

Answer revised July 2008

For cases diagnosed 2007 or later:

For the purpose of applying the Lung MP/H rules, the word "Nodule" can be used interchageably with "Tumor," "Mass," "Lesion" and "Neoplasm." HOWEVER, this does NOT apply to casefinding or staging.

This revision will be added to the next version of the MP/H rules. Sinq question 20071028 will be revised.

Answer updated April 2025

A change in the subcategory for a hormone drug does not indicate the end of First Course of Treatment because different hormone therapies generally achieve the same result. For example, some forms of breast cancer are estrogen-dependent and the various subcategories of hormone drugs used to treat them, such as gonadotropin-releasing factor agonists, aromatase inhibitors and estrogen antagonists, all achieve the same result - to block estradiol effects in these tumors.

Similarly, a change in immunotherapy is not a new course of treatment.

However, if a change to hormone therapy or immunotherapy is due to a change in the patient's ER, PR, or Her2 status, this could signify a new course of treatment.

The instruction in the SEER Manual is specific to chemotherapy. Chemotherapy is the only systemic treatment for which a change in the subcategory of a drug indicates the end of First Course of Treatment, due to the fact that different chemical agents damage cancer cells in different ways and at different phases in the cell cycle.

Answer updated August 2025

Assign code 8044/3. WHO Classification of Thoracic Tumors, 5th edition, classifies SMARCA4-deficient malignant neoplasm as Thoracic SMARCA4-deficient undifferentiated tumor (SMARCA4-UT).

Answer updated September 2025

Per consultation with a male genital and urinary subject matter expert pathologist, if a patient with a previous diagnosis of acinar adenocarcinoma (or a subtype variant of 8140/3) of the prostate was treated with radiation and/or androgen deprivation therapy (ADT, a form of hormonal therapy), the following subsequent diagnoses are NOT a new primary.

• Adenocarcinoma with neuroendocrine differentiation (8574/3)
• Adenosquamous carcinoma (8560/3)
• Small cell carcinoma (8041/3)
• Squamous cell carcinoma (8070/3)

For example, a patient is diagnosed with acinar adenocarcinoma and undergoes hormone therapy. Two years later, the patient is diagnosed with adenosquamous carcinoma. The adenosquamous carcinoma should be considered treatment-related and is not a new primary.

Any treatment that destroys or modifies cancer tissue should be recorded as the appropriate type of treatment -- chemo, immuno, etc. Even if immunotherapy is given for symptoms/palliative treatment, it is likely to kill off tumor cells.