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For unknown primaries treated with a lymph node dissection and diagnosed 1/1/2003 and after, code:

1) Surgery to Primary Site: 98 [All unknown and ill-defined disease sites, WITH or WITHOUT surgical treatment].

2) Scope of Regional Lymph Node Surgery: 9 [Unknown or not applicable].

3) Surgical Procedure of Other Site: 1 [Surgery to other site(s) or node(s), NOS; unknown if regional or distant].

4) Radiation Sequence with Surgery: 3 [Radiation after surgery]. Any planned surgical treatment is used to code radiation/surgery sequence (per CoC I&R).

Code the primary site according to the physician's opinion. An ill-defined site code or an NOS code for the organ system is preferred over C809 [Unknown primary site] whenever possible. Code C809 only when there is not enough information to use an ill-defined or NOS code.

Case 1 and Case 2 - Assign code C249 [Biliary tract, NOS]. Based on the available information, the physicians believe these are most likely biliary primaries.

Case 3 - Assign code C189 [Colon]. According to the available information, the physician believes this is most likely a colon primary.

Effective for cases coded prior to the change in policy made on January 9, 2008, code chemoembolization of a metastatic site as 1 [nonprimary surgical procedure performed] in Surgical Procedure of Other Site.

Surgery of Primary Site code 98 is assigned to all cases with an unknown primary.

In the case of a liver primary, it would be coded 10 [local tumor destruction, NOS] in Surgical Procedure of Primary Site.

Refer to the College of American Pathologists (CAP) protocols to determine how to interpret p16 staining results on pathology reports. Per the Vulva CAP Protocol, p16 positive is defined as diffuse or block-like expression. Since the pathology report states "block-like expression," code the histology as 8085/3 (invasive squamous cell carcinoma, HPV-associated).

In sites other than breast (see Breast Solid Tumor Rules M8/M9), Paget disease with underlying invasive disease is a single primary and the underlying histology is coded. Primary Paget disease of the vulva is uncommon, and we cannot create rules for all possible situations in the Other Sites module. A GYN specific module is in development, and we will look into adding a Paget-related rule. It will differ because Paget in breast is a different situation while Paget in the vulva is always adenocarcinoma.

Paget disease of the vulva is an in-situ adenocarcinoma of vulvar skin with or without an underlying adenocarcinoma (WHO Classification of Female Genital Tumors, 5th ed.). When there is a statement of “underlying” adenocarcinoma, it is a single primary as with Breast Solid Tumor Rule M8.

Assign 8077/2 for high-grade squamous intraepithelial lesion, VIN 3 in this case.  The WHO Classification of Female Genital Tumors, 5th edition, states that squamous intraepithelial lesions (SILs) of the vulva are also known as vulvar intraepithelial neoplasia, HPV-associated.  The term squamous cell carcinoma in situ is not recommended.

Table 19 is based on WHO 5th Ed Tumors of vulva and squamous cell variants, keratinizing and non-keratinizing, are no longer recommended and are excluded from the 5th Ed. HPV related terminology is now preferred for these neoplasms.

Per consultation with our GYN expert pathologist, based on the information provided, this is likely a single tumor that was not completely excised in the original biopsy. A new tumor in the same site would not appear within 8 months. If you cannot confirm two separate/non-contiguous tumors were present, abstract a single primary per M1. As for histology, the tumor showed both keratinizing and non-keratinizing features and HPV status is unclear. Per our expert, code to SCC 8070/3—keratinization or lack of does not change treatment or prognosis.

Even If there is proof of separate/non-contiguous tumors, our expert still feels this is a single primary coded to SCC 8070/3. Treatment does not differ by keratinization or HPV status. Coding two primaries would be incorrect and inflate incidence rates.

Per our expert, this is an unusual occurrence. The rules cover 85% of cases but there will always be situations that do not fit a rule. This case is an example of that.  A new GYN specific Solid Tumor Rules module is under development and a rule to address this situation could be included.

Report VIN II. The 2024 SEER Manual lists this as a separate diagnosis in the Reportability section under Malignant Histologies 1.a.x. 

For tumors diagnosed prior to 2007:

This is an example of the term "recurrent" being used loosely to refer to another primary in the urinary tract. It is highly unlikely that a bladder tumor would metastasize to the kidney. Much more likely is the field defect or regional breakdown of the urothelial tissue that lines the tract from the renal pelvis to the urethra. Furthermore, bladder tumors don't spread retrograde to the kidney. Code as two primaries.

For tumors diagnosed 2007 or later, refer to the MP/H rules. If there are still questions about how this type of tumor should be coded, submit a new question to SINQ and include the difficulties you are encountering in applying the MP/H rules.