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The WHO Classification of Hematopoietic Tumors (Blue Book), 5th edition states: “Rare cases of classic follicular lymphoma with cytological features of follicular lymphoma (FL) grade 3A can present with a prominent diffuse pattern. In the previous edition, such cases were defined as diffuse large B-cell lymphoma (DLBCL). Currently, it is uncertain whether such cases should be classified as FL or diffuse large B-cell lymphoma; and in such cases, individual treatment choices should be made in multidisciplinary conference settings taking into consideration clinical, laboratory, and imaging parameters. The presence of diffuse areas composed entirely or predominantly of large cells, however, warrants a diagnosis of diffuse large B-cell lymphoma.”

Our concern is that the Hematopoietic (Heme) Manual and Database do not provide instruction for coding this scenario. We hesitate to interpret the terms “equivalent to” as ambiguous because one could argue it is unambiguous. Barring this argument, the M and H rules would indicate this is a diagnosis of diffuse large B-cell lymphoma. However, the physician does not seem to agree with the pathologist.

The WHO Blue Books do not include dedifferentiated carcinoma as a valid histology for the breast.  However, there is known to be progression of ductal carcinoma that is essentially dedifferentiation of an estrogen receptor, progesterone receptor, and HER2 breast carcinoma to a triple negative "dedifferentiated" carcinoma which it appears this patient has. Whether we should accession this as a separate 8020/3 primary per M14 is unclear and the Solid Tumor Manual does not address this scenario.

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?

This patient had serosal involvement and the pathologist and managing physician staged this as pT4a disease. This extension seems best captured by EOD Primary Tumor code 500. Additionally, the patient had discontinuous metastatic involvement of the peritoneum, and this was staged by the pathologist and managing physician as pM1b (Intraperitoneal metastasis only, including peritoneal mucinous deposits containing tumor cells). Although this peritoneal involvement was present in the right lower quadrant, it was staged as distant metastatic disease and not as part of the primary tumor category. However, currently EOD Primary Tumor code 600 would seem to apply since the peritoneal tumor was in the right lower quadrant. Code 600 is defined as mucinous tumors with peritoneal involvement confined within right lower quadrant. This EOD Primary Tumor code and the physician’s M category assignment do not align; the physician has staged this as distant metastasis (M category, not the T category). Should the peritoneal metastasis (even limited to the right lower quadrant) be included in the EOD Mets field and not in the EOD Primary Tumor field? In other words, should the peritoneal involvement included in EOD Primary Tumor code 600 be reclassified in EOD Mets code 30 (Intraperitoneal metastasis (peritoneal carcinomatosis) WITH or WITHOUT peritoneal mucinous deposits containing tumor cells)?

Table 19: Vulva Histologies of the Other Sites Solid Tumor Rules does not include entries for either keratinizing or nonkeratinizing squamous cell carcinoma in the “Squamous cell carcinoma, NOS” row. However, these are two distinctly different histologies per the ICD-O-3.2.

All other Solid Tumor Rules schemas include an M Rule instructing one to abstract multiple primaries when separate/non-contiguous tumors are two or more different subtypes/variants in Column 3 of the Specific Histologies, NOS, and Subtype/Variants Table for the schema (e.g., Rule M6 for Lung). The timing of these tumors is stated to be irrelevant. The Notes confirm the tumors may be subtypes/variants of the same or different NOS histologies and tumors in column 3 are all distinctly different histologies (even if they are in the same row). However, the 2023 Other Sites schema appears to be missing this rule.

Should these distinctly different histologies be accessioned as separate primaries? Is an M Rule missing from the Other Sites schema to address distinctly different histologies?

Based on the EOD General instructions for accessible sites, the following three requirements must be met

a. There is no mention of regional lymph node involvement in the physical examination, pre-treatment diagnostic testing, or surgical exploration;

b. The patient has localized disease;

c. The patient receives what would be the standard treatment to the primary site (treatment appropriate to the stage of disease as determined by the physician), or patient is offered usual treatment but refuses it.

As a central registry, we receive a lot of melanoma path reports but never receive an abstract since the patients are seen at a dermatology office that does not report to the central registry. In these scenarios, we have both the diagnosis and wide excision or Mohs surgery from which we create a consolidated record. It is not often that lymph nodes are removed which indicates there were no palpable nodes.

Since the Breslow’s and Clark’s level allow for summary staging, is it possible to have central registry guidelines that allow for coding lymph nodes other than 999? The path reports meet two of the three criteria. Is there any new literature that supports coding lymph nodes 000 based on a Clark’s level or Breslow measure providing the patient has a wide excision?

There was a 3.5 cm invasive adenocarcinoma tumor in the pancreatic head. There were four separate, sized pancreatic neuroendocrine tumors measuring 0.9, 0.7, 0.5 and 0.2 cm in the pancreatic body. There are multiple tumors with distinctly different histologies. However, Table 11 (Pancreas Histologies) does not include any entries for neuroendocrine tumors of the pancreas (e.g., pancreatic NET, WHO grade 1, histology 8240). While it would seem Rule M19 should apply as they’re distinctly different histologies, because PanNETs are not included in Table 11, it is not clear which M Rule applies to these multiple tumors.

If Rule M19 does not apply, we are left with Rule M21 (Abstract a single primary when there are multiple tumors that do not meet any of the above criteria). Are these separate tumors with distinctly different histologies really a single primary? Pancreatic neuroendocrine tumors are not an uncommon histology, is there a reason these were not included in Table 11?

Patient was diagnosed in September 2022 via excision of a 12 cm pelvic mass with final diagnosis of Myofibroblastoma with sarcomatous transformation.

Diagnosis comment states, “Most of the tumor is composed of conventional features of myofibroblastoma. However, a focal area demonstrates increased cellularity, fascicular growth and increased mitotic activity (up to 11 per 10 hpf), consistent with sarcomatous transformation (morphologically low to intermediate grade).”

Is this sarcomatous transformation describing a malignant transformation from an otherwise benign histology? If so, how should histology be coded in this case?