SEER Inquiry System - Search

In the April and July 2019 updates to the Solid Tumor Rules, the term simultaneous and Note 1 indicating histologies must be the same behavior were removed from rule M10 (ductal and lobular are a single primary).

We would like to confirm that rule M10 is the correct rule to apply to this case. This case is an invasive diagnosis approximately 4.5 years after an in situ diagnosis, so it seems like M17 should apply (invasive tumor following an in situ tumor more than 60 days later are multiple primaries).

An invasive tumor following an in situ tumor more than 60 days later of the same histology is a new primary. Similarly, it seems like an invasive tumor following an in situ tumor more than 60 days later of different histologies should be a new primary.

A patient had posterior cervical lymphadenopathy status post biopsy and subsequent lymph node dissection showed metastatic melanoma in 2018. Workup showed no skin lesions or primary site. Final diagnosis is melanoma of unknown primary (unknown if cutaneous or non-cutaneous). Should C760 be used as the primary site for this case since the histology codes of 8700-8790 are included in the Cervical Lymph Nodes and Unknown Primary Tumors of the Head and Neck schema in SEER*RSA?

If the term discontinuous foci means separate tumors, then rule M14 would apply making these multiple reportable tumors.

Following the existing Solid Tumor Rules Histology Rules, it would seem this is a single primary with histology 8045 (Combined small cell carcinoma) because there is no indication there are multiple prostate tumors and Table 2 states combined adenocarcinoma and small cell carcinoma is Combined small cell carcinoma (8045).

Conversely, while not an exact match to this case, SINQ 20190083 implies small cell carcinoma and adenocarcinoma of the prostate are separate primaries. In that SINQ case, the patient was simultaneously diagnosed with metastatic small cell carcinoma of the prostate on a liver biopsy and prostate adenocarcinoma on a prostate biopsy. There is no indication that patient had separate tumors in the prostate, however the SINQ instructs to code as separate primaries.

Would the previous SINQ logic apply to synchronous diagnoses in the prostate as well? Or does code 8045 apply to this situation?

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.

Rule H13 states to code the histology to metaplastic carcinoma when there is metaplastic carcinoma (or a subtype/variant) and invasive carcinoma NST. This rule makes no mention of lobular carcinoma. However, in Table 3, Note 2 for metaplastic carcinoma (8575) states metaplastic carcinoma, NOS and subtypes are almost always mixed with invasive mammary carcinoma, NST and at times lobular carcinoma. These tumors should be coded to metaplastic regardless of percent invasive mammary carcinoma or lobular carcinoma present.

While Table 2 (the mixed histology code table) does include an entry for metaplastic carcinoma AND carcinoma NST OR lobular carcinoma, it is unclear why lobular carcinoma has not been added to Rule H13 as well.

If a single tumor has metaplastic plus lobular carcinoma, Rule H13 does not apply and one has to continue through the rules. Unfortunately, the next rule registrars would be tempted to use is Rule H18: Code the histology that comprises greater than 50% of tumor when two histologies are on different rows in Table 3. This Rule does not state it does NOT apply to metaplastic carcinoma (only mucinous). So, if for some reason the lobular was greater than 50%, the incorrect histology would be coded (unless the registrar happened to remember Note 2 in the metaplastic carcinoma entry in Table 3).

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

There is no specific ICD-O-3 code for a which resulted in abstractors assigning the malignant astrocytoma, NOS code. These lesions were previously called but we are seeing the new terminology more frequently.

The patient was diagnosed with an EBV-positive plasmablastic lymphoma involving the left testis on radical orchiectomy in April 2019.

In September 2019, a plasmacytoma was found on a right mandibular mass biopsy. Imaging at that time revealed diffuse disease involving the thoracic spine and sinus involvement. The patient then underwent a resection of the T8 spinal/epidural tumor that also proved plasmacytoma.

Subsequently, the right mandibular mass and testis slides were reviewed (at an outside facility) and both were stated to be, The T8/epidural tumor pathology was not reviewed, so it is unclear if this is also assumed to be the same disease process as the right mandibular mass or still a separate, solitary plasmacytoma.

Additionally, some chart notes indicate the patient has plasmablastic lymphoma with a secondary diagnosis of plasmacytoma, while other chart notes state this is stage IV plasmablastic lymphoma involving all documented sites. Although the plasmablastic lymphoma and at least the plasmacytoma of T8 have different ICD-O-3 histology codes, the physicians do seem to be treating this as a single disease process.

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.