SEER Inquiry System - Search

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.

Updated February 2026

For cases diagnosed 2025 and later: Assign behavior /1 for solitary fibrous tumor unless stated to be malignant or have metastasized.

A review by the Cancer PathCHART expert neuropathologists found behavior code /0 is incorrect and both solitary fibrous tumor grade 1 and grade 2 are coded as 8815/1. WHO Classification of Central Nervous System Tumors, 5th edition, assigns behavior as /1 and no longer recommends terms solitary fibrous tumor/hemagiopericytoma and hemagiopericytoma. The STR table is correct. Future updates to ICD-O should reflect this behavior.

WHO Classification of Tumours, Central Nervous System Tumours, 5th ed. was reviewed by the CPC expert pathologists for implementation for cases diagnosed January 1, 2025.

Reminder: Comparing the CPC Validity Status included in the 2024 CPC*Search to that included in the 2025 SMVL (that table that drives the edits) is incorrect. CNS Tumors were not reviewed for 2024 implementation, they were reviewed for 2025 implementation. There will be a 2025 CPC*Search and a /1 will be designated as a Valid.

Do not report superficial CD34-positive fibroblastic tumor (8810/1) of the thigh.

WHO Classification of Soft Tissue and Bone Tumors, 5th ed., defines superficial CD34-positive fibroblastic tumor as a distinctive low-grade neoplasm of the skin and subcutis, most frequently occurring in the lower extremities, especially thigh, followed by arm, buttock, shoulder, and rarely, vulva.

Histology code 8255/3 best identifies this histology. Complex glands in lung tumors are often associated with a poor prognosis and represent a high-grade pattern in lung cancer grading systems. This histology is not currently recognized as a variant by WHO. 

Do not include the disease in the sequencing if the original hematolymphoid disease was not reportable at time of diagnosis.

The 2025 SEER Manual Sequence Number--Central Coding Instruction 1.a advises: A ‘reportable’ primary refers to the site/histology/behavior of the tumor and the years when reporting was required. Review of the reportability requirements in effect during the diagnosis year will be needed.

Code the primary site to pelvic lymph nodes (C775) as it is the only site involved with this extrapulmonary lymphangioleiomyomatosis (E-LAM).

Do not assign a behavior code of /2 to these cases unless you have a way to flag them so that they are not reported to the standard setters as in situ cases. Work with your state central registry to ensure that these cases are not unintentionally included in state case submission.

Code meningioma, NOS (9530/0) based on the integrated diagnosis and histological classification. WHO Classification of Central Nervous System Tumors, 5th edition, states that brain invasion is a criterion for the diagnosis of CNS WHO grade 2 meningioma, and there is no statement of brain invasion, atypical meningioma, or other WHO grade 2 lesions. WHO has not proposed behavior codes based on WHO grade alone.

Assign 8020/3 for SMARCA4- deficient malignant neoplasms of the esophagus.

The WHO Classification of Digestive System Tumors, 5th edition, lists undifferentiated carcinoma as 8020/3. Undifferentiated carcinoma of the esophagus is characterized by the frequent loss of SMARCA4 or SMARCA2 by immunohistochemistry.

SINQ 20200057 was updated in August 2025 and assigns code 8044/3 for Thoracic SMARCA4-deficient undifferentiated tumor (SMARCA4-UT). The 2025 Solid Tumor Manual includes SMARCA4-deficient or SMARCB1-deficient tumors for thoracic and sinonasal sites (8044/3).

Assigning histology to other individual sites should be on a case-by-case basis.

Report the case when the differential diagnosis includes only reportable neoplasms in the absence of additional information. We are unable to provide general instructions for provisional diagnoses as each situation will need to be reviewed and assessed individually when no further work-up information is available.

Assign myeloid leukemia, NOS (9860/3) to the case described in the example. Assign a generic histology code because a specific histology code cannot be assigned when there are several differential diagnoses. Since the differential diagnoses include a chronic and an acute leukemia, code as myeloid leukemia, NOS since it is not clear if this is chronic or acute.