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Update February 2026, note added:

Report this case as smoldering myeloma (9732/3) based on the plasma cell 10% threshold and favorable cytogenetics and lack of organ dysfunction (9732/3). According to the College of American Pathologists Plasma Cell Malignancies Protocol, in order to code smoldering multiple myeloma, both criteria must be met:

• Serum monoclonal protein (IgG or IgA) ≥3gm/dL, or urinary monoclonal protein ≥ 500 mg per 24h and/or clonal bone marrow plasma cells 10-60%

• Absence of myeloma defining events or amyloidosis.

Note: This case was answered by our expert pathologist and applies to this case only. Registrars should not use the plasma cell threshold to determine reportability or histology. The diagnosis must come from the pathologist or the managing physician.

Code as a localized, intracapsular tumor as ductal carcinoma in situ does not invade. Intraductal spread is describing the neoplasm spreading through the acinar/ductal cells in the prostate specimen. It is an in-situ type of spread and not invasive but almost always presents with an invasive tumor.

When there is neoadjuvant therapy followed by surgery, do not record the size from the pathologic specimen. Code the largest size of the tumor prior to neoadjuvant treatment; if unknown code size as 999. We will remove Coding Instruction 12.a.i in the next version of the manual.

The NAACCR Annotated Histology List (AL) serves as an aid to registry software vendors for implementing annual histology changes. This file has been maintained by the Registry Plus team at CDC’s NPCR for several years and reflects modifications to ICD-O-3 implemented by North American cancer registries over time. Although this list is reviewed multiple times prior to posting, there is no guarantee of 100% accuracy. 

As such, the AL is not a substitute for referring to various standard-setter documents and implementation guidelines. In this instance, Medulloblastoma Desmoplastic SHH-activated and TP53-wildtype 9471 is across several resources: the Solid Tumor Rules, Malignant CNS and Peripheral Nerves module in Table 3, column 3  as a subtype/variant of Medulloblastoma NOS 9470; in the CNS WHO 5th Edition BB; and in the WHO IARC ICD-O-3.2 posted to  ICD O 3 Coding Updates (naaccr.org). Although the exact related term of Medulloblastoma, SHH-activated, NOS is not listed, the NAACCR Implementation Guidelines for 2024 recommend checking the 2024 ICD-O-3 Update Table 1 or 2 to determine if the histology is listed. If the histology is not included in the update, then review ICD-O-3.2 and/or Hematopoietic and Lymphoid Database and/or Solid Tumor Rules (MP/H).

The Cancer PathCHART initiative has been undertaken to address gaps such as this between standard setting resources. Having all the standard histology coding resources included in a single all-inclusive database enables alignment of morphology codes & terms included in the CPC*SMVL (Cancer PathCHART Site-Morphology Validation List), Solid Tumors Rules, ICD-O-3 Annual Updates, NAACCR Annotated Histology List as well as the WHO 5th edition Blue Books. Please see Cancer PathCHART - Tumor Site-Morphology Surveillance Standards Initiative for more information on the Cancer PathCHART initiative, and more specifically, see Transitioning the Annotated Histology List to Cancer PathCHART (naaccr.org).

Report high grade serous intraepithelial neoplasm of the endometrium. 

Code SEER Summary Stage 2018 to Localized, Code 1. Per consult with AJCC and noted in the Primary Peritoneal Chapter in AJCC 8th edition, an intraoperative rupture is coded as a surgical spill. 

A capsule rupture is when the capsule ruptures prior to the surgery (Summary Stage Regional, Code 2). 

Report this case of leukemia cutis and code to bone marrow (C421) and leukemia NOS (9800/3) based on the information provided. Update the abstract if new information becomes available.

Leukemia cutis is the rare infiltration of neoplastic leukocytes into the epidermis, dermis, or subcutis from an existing leukemia that results in clinically identifiable cutaneous lesions. Leukemia cutis may precede, follow, or occur concurrently with the diagnosis of systemic leukemia. It is an advanced phase of the leukemia having a poor prognosis that also strongly correlates with additional sites of extramedullary involvement. This can alter the appropriate treatment regimen for a patient. It is a type of "metastasis" or spread of the leukemia cells. The "conventional" definition for leukemia cutis is the infiltration of skin from a bone marrow primary. It is most often diagnosed via skin biopsy—punch, shave, etc., utilizing IHC/biomarker testing and is commonly associated with CMML and acute myeloid leukemia (AML). As such, it a reportable condition especially when preceding a confirmed systemic leukemia diagnosis. In this situation, the diagnosis date would be the date of the positive leukemia cutis skin bx—punch, shave, etc. The case should be coded to C421; 9800/3 Leukemia NOS until the official systemic leukemia diagnosis is rendered. If possible, follow back should be conducted to determine the specific systemic leukemia histology (CMML; AML) and the treatment received. If the leukemia cutis follows or occurs concurrently with the diagnosis of a systemic leukemia, it is NOT a separate primary but merely an advanced stage of the systemic leukemia diagnosis.

Code Primary Site to C480 (retroperitoneum). 

Endometrial tissue may "break away” from the uterus and implant throughout the pelvic and abdominal cavities. This can occur in patients who suffer from endometriosis. This tissue remains behind when surgical removal of the uterus is done. Common sites of implantation are colon, peritoneum, retroperitoneum, and bladder. These cells may become malignant. When the uterus is no longer present (patient had surgical removal), code the site where the carcinoma was identified.

The site-morphology combination of C480 and 8380/3 was designated as an unlikely site-morphology combination by the Cancer PathCHART expert pathologist review, as this is a rare type of tumor. Assign a value of 1 in the Over-ride Site/Type [2030] data item in order to pass the Primary Site, Morphology-Type, Beh ICDO3, 2024 (SEER) edit.

Assign histology as DLBCL (9680/3) as supported by the WHO Classification of Hematolymphoid Tumors, 5th edition. It is consistent with how it would have been coded in the 4th edition. The Heme Manual and Database currently are based on the 4th edition. Physicians are using the 5th edition blue book, whereas the cancer registry field is not yet at this time.

Regarding the Heme Manual and Database, this type of scenario is not covered because it is part of the 5th edition WHO Blue Book. The database cannot be updated until the 5th edition is approved for implementation (2026).

Sites may be added to certain combinations when indicated by ClinCORE review for Cancer PathCHART. Please note some sites were added in the 2024 update as a result of PathCHART review. A newly-formed Solid Tumor Editorial Board and its subgroups are currently working to evaluate the Solid Tumor Manual and make recommendations on ways to improve the structure and formatting of the manual and its content.

Follow the rules and instructions in the Other Sites STRs when assigning combination histology codes.

Histology Coding Rules

Use the Histology Coding Rules when assigning combination codes.

Coding Histology Information

Use this section that includes the mixed histology (Table 2) and site-specific histology tables (Tables 3-23) for one or more histologies within a single tumor. Do not use this section in place of the Histology Coding Rules.

While site-specific histology tables, based on current WHO Classification of Tumors books, have been added to Other Sites STRs, not all site groups have individual histology tables; coding may require the use of ICD-O and updates. The histology tables in Other Sites STRs include additional coding instructions and notes to assign the correct ICD-O code when appropriate.

The tables are not meant to be all-inclusive; rather they are intended to address difficult coding situations to facilitate the assignment of the correct histology code.

Table 2: Mixed and Combination Codes Instructions

Once you have identified the histology terms and have been instructed to use Table 2 by the Histology Coding Rules, compare the terms in the diagnosis to the terms in Column 1. When the terms match, use the combination code listed in Column 2. Use adenocarcinoma mixed subtypes 8255 as a “last resort” code.