C77.2 ICD-10-CM Code: Secondary and unspecified malignant neoplasm of intra-abdominal lymph nodes
C77.2 maps to CMS-HCC V28 18. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC Buddy coding tools
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FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of ill-defined, other secondary and unspecified sites (C76-C80)
C77.2
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceSecondary and unspecified malignant neoplasm of intra-abdominal lymph nodes
Cancer that has spread to or originated in the lymph nodes located in the abdominal cavity.
Buddy Insight
Secondary and unspecified malignant neoplasm of intra-abdominal lymph nodes represents metastatic cancer involving mesenteric, retroperitoneal, celiac, or other abdominal lymph nodes.
CMS-HCC V28
MappedHCC 18
Coefficient HCC 18: 2.341 (Community Non-Dual Aged (CNA))
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
MappedHCC 008
Code-level coefficient reference
ESRD/PACE
MappedHCC 8
Code-level coefficient reference
RXHCC
MappedHCC 20
Code-level coefficient reference
Code Book Path
Inclusion Terms
OfficialNo inclusion terms are included in this display for C77.2. Check the code and parent instructions in the Code Book.
Excludes 2
OfficialNo Excludes 2 notes are included in this display for C77.2. Check the code and parent instructions in the Code Book.
Related Codes
Includes
OfficialNo Includes notes are included in this display for C77.2. Check the code and parent instructions in the Code Book.
Excludes 1
Official- malignant neoplasm of lymph nodes, specified as primary (C81-C86, C88, C96.-)Inherited from C77
- mesentery metastasis of carcinoid tumor (C7B.04)Inherited from C77
- secondary carcinoid tumors of distant lymph nodes (C7B.01)Inherited from C77
Code First
OfficialNo Code First sequencing instructions are included in this display for C77.2. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for C77.2. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for C77.2. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
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 C77.2 an HCC code?
Yes. C77.2 (Secondary and unspecified malignant neoplasm of intra-abdominal lymph nodes) maps to HCC 18, Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 2.341. 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: C77.2 is billable and maps to V28 HCC 18, Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- C77.2
- Description
- Secondary and unspecified malignant neoplasm of intra-abdominal lymph nodes
- HCC (V28)
- HCC 18 — Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid
- RAF reference coefficient
- 2.341
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
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 C77.2 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for C77.2
For C77.2, 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
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What This Code Means
C77.2 is the ICD-10-CM diagnosis code for secondary and unspecified malignant neoplasm of intra-abdominal lymph nodes. Cancer that has spread to or originated in the lymph nodes located in the abdominal cavity. C77.2 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of ill-defined, other secondary and unspecified sites (c76-c80).
Under the CMS-HCC V28 risk adjustment model, C77.2 maps to Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid (HCC 18) with a source-labeled community, non-dual, aged reference coefficient of 2.341. 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.
This code includes malignancies of retroperitoneal, mesenteric, and other intra-abdominal lymph nodes. For C77.2, 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 C77.2 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This code includes malignancies of retroperitoneal, mesenteric, and other intra-abdominal lymph nodes
- •Identify and code the primary cancer site separately if this represents metastatic disease
Clinical Significance
Secondary and unspecified malignant neoplasm of intra-abdominal lymph nodes represents metastatic cancer involving mesenteric, retroperitoneal, celiac, or other abdominal lymph nodes. Common primaries include gastrointestinal cancers, gynecologic cancers, and genitourinary cancers. Intra-abdominal nodal metastasis often signifies advanced disease staging.
Documentation Requirements
- ✓Imaging (CT abdomen, PET scan) confirming malignant intra-abdominal lymphadenopathy
- ✓Pathology when available (image-guided biopsy, surgical specimen)
- ✓Identification and separate coding of the primary malignancy
- ✓Specific lymph node groups involved (mesenteric, retroperitoneal, para-aortic, celiac)
- ✓Treatment plan and staging implications
Commonly Confused Codes
- •C77.5: Intrapelvic lymph nodes: Different regional group; distinguish abdominal from pelvic nodes
- •C77.0: Head, face, neck lymph nodes: Different anatomical region
- •C78.6: Secondary malignant neoplasm of retroperitoneum: Retroperitoneal metastasis to tissue, not lymph nodes
- •C81-C86: Lymphomas: Primary lymph node malignancy, not secondary
- •C48.0: Malignant neoplasm of retroperitoneum: Primary retroperitoneal tumor, not metastatic lymph nodes