C41.4 maps to CMS-HCC V28 21. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · free HCC coding tools

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupC41.4

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of bone and articular cartilage (C40-C41)

C41.4

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Malignant neoplasm of pelvic bones, sacrum and coccyx

This code represents cancer that originates in the bones of the pelvis, sacrum (the large triangular bone at the base of the spine), or coccyx (tailbone). These are primary bone cancers rather than cancer that has spread to these bones from elsewhere.

Buddy Insight

Primary malignant neoplasm of the pelvic bones, sacrum, and coccyx.

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

Mapped

HCC 21

Lymphoma and Other Cancers

Coefficient HCC 21: 0.671 (Community Non-Dual Aged (CNA))

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Mapped

HCC 010

HHS-HCC 010 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 10

Lymphoma and Other Cancers

Code-level coefficient reference

RXHCC

Mapped

HCC 22

Prostate, Breast, Bladder, an...

Code-level coefficient reference

Code Book Path

Official

C41Malignant neoplasm of bone and articular cartilage of other and unspecified sites C41.4Malignant neoplasm of pelvic bones, sacrum and coccyx

Inclusion Terms

Official

No inclusion terms are included in this display for C41.4. Check the code and parent instructions in the Code Book.

Excludes 2

Official

No Excludes 2 notes are included in this display for C41.4. Check the code and parent instructions in the Code Book.

Related Codes

Official

C41.0Malignant neoplasm of bones of skull and face C41.1Malignant neoplasm of mandible C41.2Malignant neoplasm of vertebral column C41.3Malignant neoplasm of ribs, sternum and clavicle C41.9Malignant neoplasm of bone and articular cartilage, unspecified

Includes

Official

malignant neoplasm of cartilage (articular) (joint)Inherited from C40-C41
malignant neoplasm of periosteumInherited from C40-C41

Excludes 1

Official

malignant neoplasm of bone marrow NOS (C96.9)Inherited from C40-C41, C41
malignant neoplasm of synovia (C49.-)Inherited from C40-C41, C41
malignant neoplasm of bones of limbs (C40.-)Inherited from C40-C41, C41
malignant neoplasm of cartilage of ear (C49.0)Inherited from C40-C41, C41
malignant neoplasm of cartilage of eyelid (C49.0)Inherited from C40-C41, C41
malignant neoplasm of cartilage of larynx (C32.3)Inherited from C40-C41, C41
malignant neoplasm of cartilage of limbs (C40.-)Inherited from C40-C41, C41
malignant neoplasm of cartilage of nose (C30.0)Inherited from C40-C41, C41

Code First

Official

No Code First sequencing instructions are included in this display for C41.4. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for C41.4. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for C41.4. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Specific bone involved (ilium, ischium, pubis, sacrum, or coccyx)

Histologic type — sacral chordoma is the most common primary sacral tumor

Primary vs. metastatic origin confirmed — pelvic bone metastases are far more common

Tumor staging and imaging extent

MEAT Support

HCC Buddy guidance

Specific bone involved (ilium, ischium, pubis, sacrum, or coccyx)

Histologic type — sacral chordoma is the most common primary sacral tumor

Primary vs. metastatic origin confirmed — pelvic bone metastases are far more common

Tumor staging and imaging extent

Audit Caution

HCC Buddy guidance

Coding sacral tumors under C41.2 (vertebral column) instead of C41.4 — the sacrum is classified with pelvic bones, not the vertebral column

Confusing primary pelvic bone malignancy with the far more common pelvic bone metastases from prostate or colon cancer

Using this code for rectal or gynecologic cancers that invade the sacrum — those are primary visceral cancers with local extension

Miscoding multiple myeloma involving the pelvis as primary bone cancer — myeloma uses C90.x codes

Common Mistakes

HCC Buddy guidance

C41.2 — Malignant neoplasm of vertebral column; the sacrum is coded under C41.4, NOT C41.2

C79.51 — Secondary malignant neoplasm of bone; pelvic metastases from prostate, breast, and colon cancer are very common

C76.3 — Malignant neoplasm of pelvis; this is for unspecified pelvic site, not bone-specific

C41.0 — Malignant neoplasm of skull/face; different axial site

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is C41.4 an HCC code?

Yes. C41.4 (Malignant neoplasm of pelvic bones, sacrum and coccyx) maps to HCC 21, Lymphoma and Other Cancers under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.671. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: C41.4 is billable and maps to V28 HCC 21, Lymphoma and Other Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: C41.4
Description: Malignant neoplasm of pelvic bones, sacrum and coccyx
HCC (V28): HCC 21 — Lymphoma and Other Cancers
RAF reference coefficient: 0.671
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 21, Lymphoma and Other Cancers

0.671

ESRDHCC 10, Lymphoma and Other Cancers

Not separately weighted

RxHCCHCC 22, Prostate, Breast, Bladder, and Other Cancers and Tumors

Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work C41.4 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for C41.4

For C41.4, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Coder workflow notes

Get the V28 mapping + MEAT cheat sheet

One printable reference: check representative V28 mappings and the documentation reminders your note needs. Free, no card.

Free PDF. No card. Unsubscribe anytime.

What This Code Means

C41.4 is the ICD-10-CM diagnosis code for malignant neoplasm of pelvic bones, sacrum and coccyx. This code represents cancer that originates in the bones of the pelvis, sacrum (the large triangular bone at the base of the spine), or coccyx (tailbone). These are primary bone cancers rather than cancer that has spread to these bones from elsewhere. C41.4 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of bone and articular cartilage (c40-c41).

Under the CMS-HCC V28 risk adjustment model, C41.4 maps to Lymphoma and Other Cancers (HCC 21) with a source-labeled community, non-dual, aged reference coefficient of 0.671. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

Verify whether the cancer is primary (originated in the bone) or secondary (metastatic from another site), as secondary bone cancers use different codes. For C41.4, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for C41.4 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Verify whether the cancer is primary (originated in the bone) or secondary (metastatic from another site), as secondary bone cancers use different codes
•Document the specific bone location (pelvis, sacrum, or coccyx) in the medical record to support accurate code selection and ensure specificity

Clinical Significance

Primary malignant neoplasm of the pelvic bones, sacrum, and coccyx. This site includes chordoma (most common sacral tumor), chondrosarcoma, osteosarcoma, and Ewing sarcoma of the pelvis. These tumors are often large at diagnosis due to the deep anatomic location and carry significant surgical morbidity. Distinction from pelvic metastases is critical.

Documentation Requirements

✓Specific bone involved (ilium, ischium, pubis, sacrum, or coccyx)
✓Histologic type — sacral chordoma is the most common primary sacral tumor
✓Primary vs. metastatic origin confirmed — pelvic bone metastases are far more common
✓Tumor staging and imaging extent
✓Involvement of sacral nerve roots or pelvic organs
✓Treatment plan and functional impact assessment

Commonly Confused Codes

•C41.2: Malignant neoplasm of vertebral column; the sacrum is coded under C41.4, NOT C41.2
•C79.51: Secondary malignant neoplasm of bone; pelvic metastases from prostate, breast, and colon cancer are very common
•C76.3: Malignant neoplasm of pelvis; this is for unspecified pelvic site, not bone-specific
•C41.0: Malignant neoplasm of skull/face; different axial site