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Insulinoma, NOS is reportable for cases diagnosed 2021 and later. However, the diagnosis of insulinoma is most frequently made with clinical correlation of the patient's clinical syndrome and serum hormone levels. Despite a pathological diagnosis of NET, this will clinically be stated as insulinoma based on the functional type of tumor. At the largest facility in our area, all pathology reports with a diagnosis of insulinoma over the last year only provide a pathological Final Diagnosis of NET (either G1 or G2), but elsewhere specify, Functional Type: Pancreatic neuroendocrine tumor, functional. Correlation with Clinical Syndrome and Elevated Serum Levels of Hormone Product: Insulin-producing (Insulinoma).

For 2021 and later, it seems this should be accessioned as insulinoma (8151/3), but one cannot arrive at that histology using the current Other Sites (MP/H) H Rules. Following the existing rules, one would code the histology to NET, G1 or NET, G2 (8240 or 8249) per Rule H6. There are technically two specific histologies to consider: NET (either 8240 or 8249) and insulinoma, NOS (8151). Following the H Rules, Rule H6 instructs one to code the histology with the numerically higher ICD-O-3 code (8240 or 8249).

Coding this histology to NET (8240 or 8249) does not seem to reflect the most accurate classification of this tumor, but applying the current rules, this is the only histology that can be coded. There is no current guideline in the Other Sites schema or the ICD-O-3.2 Implementation Guidelines instructing us to ignore the pathological diagnosis of a NET for these tumors (even though insulinomas are NETs). The only SINQ that currently exists (SINQ 20150019) states the histology can be coded as either a NET or an insulinoma in these cases. How are registrars to consistently code histology for these tumors without a rule clarification?

This question was prompted from preparing SEER*Educate coding exercises. We will use the answer as a reference in the rationales.

Patient has a resection labeled as: Spine, designated intramedullary lesion. The Final Diagnosis is: Melanocytic neoplasm with features most consistent with primary intramedullary melanocytoma. The Diagnosis Comment states: The overall immunophenotypic and morphologic impression is a primary central nervous system melanocytoma.

The ICD-O-3 lists melanocytoma, NOS histology code as 8726/0, but does not provide a site-associated code. If the ICD-O-3 is used, the histology would be 8726/0 and the primary site presumably would be C720 since the tumor was specifically described as being intramedullary (i.e., within the spinal cord medulla).

Table 6 (Solid Tumor Rules, Non-Malignant CNS Equivalent Terms and Definitions) does not list either an intramedullary melanocytoma or melanocytoma (NOS). However, Table 6 does include meningeal melanocytosis 8728/0 and meningeal melanocytoma 8728/1. If Table 6 is used and the histology is coded 8728/1, then the primary site would presumably be C701 per the ICD-O-3 site-associated listing for this histology (C709).

Is this histologic terminology synonymous with 8071/2 Differentiated-type vulvar intraepithelial neoplasia?

Per the 7/20/2018 updates to the 2018 ICD-O-3 Histology list, the reportability flag was changed from N to Y for Differentiated-type vulvar intraepithelial neoplasia as well as Differentiated penile intraepithelial neoplasia, both 8071/2. It appears that both SINQ 20180020 and the second half of SINQ 20160069 are no longer valid and should be deleted.

Per Mayo consulting pathologist, the final diagnosis on this right lung biopsy is: SMARCA4-deficient malignant neoplasm (see Comment). Comment: Sections show a poorly-differentiated malignant neoplasm without any apparent glandular, squamous, or stromal differentiation. The tumor near totally replaces the underlying lung tissue without recognizable underlying alveolar parenchyma. Immunohistochemical stains performed at Mayo Clinic (Oscar keratin, INSM1, NUT, S100, desmin and BRG1 protein encoded by SMARCA4 gene) demonstrate that the malignant cells are positive for Oscar keratin (rare cells only), synaptophysin (weak/patchy) and p63 (focal) while negative for the remaining antibodies tested. Of note, SMARCA4 stain is negative in the tumor cells. Thus, this tumor can be categorized as a SMARCA4-deficient malignant neoplasm, which is known to be an aggressive malignancy, likely represent a SMARCA4-deficient thoracic sarcoma, a recently described entity. SMARCA4-deficient carcinomas in the lung have been reported to be mostly adenocarcinomas or squamous cell carcinomas, which would not fit for this case. Please refer to a paper published by our group (Sauter JL et al. Mod Pathol 2017;30:1422-32.

Lip has not been added to any of the site-specific histology tables, nor has any other instruction been provided for coding tumors in this site.

Coding histology for lip primaries is difficult because registrars do not know where to look first. The Solid Tumor Rules indicate one should use the tables first, but then do not inform registrars what table to use for a lip primary (i.e., a specific table, any table, no table).

This question was prompted from preparing SEER*Educate coding exercises. We will use the answer as a reference in the rationales.

Examples:

1) New tumor at the ileocolic anastomosis, described as a, Circumferential centrally ulcerated mass with raised borders. Tumor extension: Tumor invades through muscularis propria into subserosal adipose tissue, no involvement of the serosal surface identified. The only mention of mucosa on the resection is the uninvolved enteric mucosa or uninvolved colonic mucosa in the otherwise uninvolved portions of the ileum/colon. If neither bullet 1 or 2 apply, is this a new primary per M7 bullet 3?

2) Right colon with anastomosis site. Tumor site: Anastomosis. Tumor extension: Tumor invades through the muscularis propria. Gross description does not describe mucosa, only noting, at the central area of anastomosis is an ill-defined, slightly raised, tan-brown to purple mass measuring 2.2 x 2 cm, which is nearly circumferential, causing obstruction at the site of anastomosis. If neither bullet 1 or 2 apply, is this a new primary per M7 bullet 3?

3) Polyp at ileocolonic anastomosis, polyp biopsy final diagnosis was, Invasive moderately differentiated colonic adenocarcinoma in association with adenoma. No mention of mucosa on the biopsy final diagnosis or gross description. Clinical info indicates, There is an ulcerated 5 cm mass at the ileo-colonic anastomosis that was biopsied. If neither bullet 1 or 2 apply, is this a new primary per M7 bullet 3?

Table 1 of the 2018 Kidney Solid Tumor Rules (STR) lists succinate dehydrogenase-deficient renal cell carcinoma as histology code 8312, but in the ICD-O-3.2 Coding Table it is listed as histology code 8311.

No changes were made in the Kidney STR. As a result, the histology change described in the ICD-O-3.2 Coding Table conflicts with Table 1. Succinate dehydrogenase-deficient renal cell carcinoma (SDHD) is listed in Table 1 as a synonym for renal cell carcinoma, NOS (8312). However, the ICD-O-3.2 Coding Table lists this as a related term for histology code 8311/3. This related term was not discussed in the Implementation Guidelines, and no change was noted in the STR.

While it seems we should continue to follow the STR, without clarification as to why this histology change was not implemented in STR, achieving consistency will be problematic if registrars jump straight to the ICD-O-3.2 Coding Table to code histology for cases diagnosed 2021 and later. If this code cannot be used for cases diagnosed prior to 2021, should that clarification be included in the STR?

This question was prompted from preparing SEER*Educate coding exercises. We will use the answer as a reference in the rationales.

Rule H4 states: Code 8723/3 (malignant melanoma, regressing) when the diagnosis is regressing melanoma. However, if the diagnosis was strictly regressing melanoma or malignant melanoma, regressing, the first rule that applies is Rule H1 because regressing melanoma is a single, specific histologic type and Rule H1 states: Code the histology when only one histologic type is identified. Following the current rules, one would never arrive at Rule H4. Should the H Rules be reordered? Or should an example of when one would use Rule H4 be added to clarify when to use this rule?