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Previous SINQ 20091100 has a similar scenario and the instruction was to code as lentigo maligna (8742/2); however, it does not appear to be applicable to cases diagnosed after 2020.

The WHO Blue Book does not list melanoma, lentiginous type or lentiginous melanoma in situ as an alternate term for lentigo maligna and neither do the STR or the ICD-O-3.2.

There was a single right fallopian tube tumor with two distinct morphologies. The diagnosis comment states, “The combined morphologic and immunohistochemical features are best classified as primary fallopian tube high grade serous carcinoma with a somatically derived yolk sac tumor.”

Laryngeal intraepithelial neoplasia II-III is not included in the ICD-O-3.2 and, while the SEER Program Coding and Staging Manual (SPCSM) confirms this is reportable, neither the SPCSM nor the Solid Tumor Rules Manual provide the specific histology to use for LIN II or LIN III. Should this be coded as 8077/2 since this is most like a high grade squamous dysplasia?

There are two histologies provided in the final diagnosis, malignant spindle cell neoplasm (8004/3) and atypical fibroxanthoma (8830/3). There is a definitive diagnosis of the non-specific histology, but the more specific histology is only described using ambiguous terminology.

The external ear (C442) is included in the Head and Neck schema for diagnosis year 2018 and later. The Head and Neck Histology Rules indicate ambiguous terminology cannot be used to code a more specific histology. So ignoring the atypical fibroxanthoma, because it is modified by ambiguous terminology, we are left with a non-reportable site and histology combination (C442, 8004/3).

Diagnoses of malignant atypical fibroxanthomas are regularly diagnosed using the syntax above in our area. Follow-up with the physician or pathologist is generally not possible as these cases are received from dermatopathology clinics only. The pathology report is the only information that will be received. If the reportable diagnosis of malignant atypical fibroxanthoma is ignored per the current Solid Tumor Rules, incidence cases will be lost.

Histologic Type: HPV-associated multiphenotypic carcinoma. Overall, the morphology, immunohistochemistry, and HPV testing results support the diagnosis of an HPV-related multiphenotypic carcinoma. This entity has been described in the sinonasal region, where it behaves more indolently than its other salivary gland carcinoma counterparts (e.g., adenoid cystic carcinoma), with local recurrence but rare metastases.

Example: Patient had a 2023 nasopharyngeal mass biopsy showing “Nasopharyngeal non-keratinizing squamous cell carcinoma, undifferentiated type.” 

The Head and Neck Solid Tumor Rules (STRs) do not include an H Rule that instructs us how to code histology when there are two subtypes/variants present for a head and neck primary, nor does the STR define undifferentiated carcinoma as a subtype/variant for 8072.

The WHO Classification of Head and Neck Tumors states non-keratinizing nasopharyngeal carcinoma (non-keratinizing squamous cell carcinoma (SCC) is the most common subtype for nasopharyngeal ca, but that non-keratinizing can be subdivided into undifferentiated and differentiated subtypes.

Should histology be 8020 (undifferentiated carcinoma) or 8072 (non-keratinizing SCC)?

The 2024 Solid Tumor Rules, Table 5: Tumors of the Oropharynx, Base of Tongue, Tonsils, Adenoids contain notes that say beginning 1/1/2022, keratinizing or non-keratinizing SCCs, HPV positive or HPV negative, are coded 8085 or 8086, respectively, for sites listed in the Head and Neck Solid Tumor Rules, Table 5 only.

Table 5 introductory section also states for cases diagnosed 1/1/2023 forward: “When the diagnosis is a subtype/variant of squamous cell carcinoma and HPV status is also noted, code the subtype/variant.” This latter instruction is also included in Other Sites Table 23 (Penis and Scrotum Histologies) as a “Penis Coding Note.”

Do these instructions ONLY apply to sites on those tables (and only to Penis or to Scrotum also in Table 23)? How should we code HPV-related keratinizing/non-keratinizing or other subtype/variant SCCs, for sites NOT on those tables, given the fact that only the more common histologies are listed in the Solid Tumor tables? For example, we recently reviewed a case with HPV-positive basaloid squamous cell carcinoma of the anus (C21.0).

1.  The 2022 and 2023 SEER Program Coding Manuals state under Histologic Type ICD-O-3: Beginning with cases diagnosed 01/01/2022 forward, p16 test results can be used to code squamous cell carcinoma, human papilloma virus (HPV) positive (8085) and squamous cell carcinoma, HPV negative (8086).

NAACCR 2023 Implementation Guidelines contain similar instructions on HPV histologies for cervix, vulva and vagina that are applicable back to 2022 (2021 for cervix).

The current Other Sites Solid Tumor Rules state on the Histology tables for anus, cervix, vagina, vulva, and penis and scrotum: "p16 is a valid test to determine HPV status and can be used to code HPV associated and HPV independent histologies." Since Other Sites Solid Tumor Rules apply to cases diagnosed 2023+, can p16 results only be used from 2023 onward, to code HPV-related histologies for primaries that fall under the Other Sites module? Or per the 2022 SEER Manual statement and NAACCR 2023 Implementation Guidelines, could a p16-confirmed HPV histology code also apply to a 2022 Other Sites case and if so, is that only for cervix, vulva, and vagina? Further complicating the matter are the 2024 ICD-O-3.2 update documents indicating these codes are valid 1/1/2024+ for the “Other Sites” penis and scrotum.

2.  Is using p16 testing for HPV-related histology codes ONLY allowed for sites in the Solid Tumor tables that contain the statements about p16 (Head & Neck Table 5, and the Other Sites tables noted above for anus, cervix, etc.)? Or could it apply to primary sites outside of those tables; for example, a 2022 pathology report from the ethmoid sinus C311 indicating an HPV-related histology based on p16 testing? The ICD-O-3 Annotated Histology lists include C310-C313 among the common site codes for 8085 and 8086. The Head and Neck Solid Tumor Rules “New for 2022” section and rule H1 Note 4 also mention that p16 can be used to code HPV histologies; these sections would seem to apply to all sites in that module, since only the more common histology codes are listed in the tables and if not, we are instructed to use ICD-O.

In 01/2023, right lower lobectomy final diagnosis proved a single adenocarcinoma tumor with the histological patterns described as acinar (20%), papillary (30%) and solid; complex glands (cribriform and fused glands) (50%). There is no H Rule applicable to a complex glandular pattern adenocarcinoma. Is this equivalent to a solid predominant adenocarcinoma (8230) per Rule H7? Or is the predominant adenocarcinoma a mixed subtype coded as 8255 per Rule H9?

Small cell carcinoma is a specific type of neuroendocrine carcinoma for the lung. However, Table 3 lists neuroendocrine carcinoma, NOS as the more specific subtype/variant in Column 3.

Using Lung Solid Tumor Rules, Rule H6, a diagnosis of poorly differentiated neuroendocrine carcinoma (small cell carcinoma)” would be coded as 8246, instead of 8041, because there are two histologies under consideration (an NOS and a subtype/variant in Table 3), and the rule tells us to code the subtype/variant. However, small cell carcinoma is more specific than the NOS diagnosis (neuroendocrine carcinoma, NOS). Should Table 3 be updated to reflect which histology is the NOS and which is the more specific?