2026 ICD-10-CM Diagnosis Code C77.4Secondary and unspecified malignant neoplasm of inguinal and lower limb lymph nodes
ICD-10-CM Codes›C00–D49›C76-C80›C77
- Billable — Valid for Submission
- Chronic Condition
C77.4 is a billable ICD-10-CM diagnosis code for secondary and unspecified malignant neoplasm of inguinal and lower limb lymph nodes. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 820 through 825, 840 through 842. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Secondary malignancies.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Metastasis to lymph node from adenocarcinoma
- Metastatic adenocarcinoma to lymph node of lower limb
- Metastatic carcinoma to lymph node of lower limb
- Metastatic malignant neoplasm to femoral lymph nodes
- Metastatic malignant neoplasm to inguinal lymph nodes
- Metastatic malignant neoplasm to inguinal region
- Metastatic malignant neoplasm to lymph nodes of lower limb
- Metastatic malignant neoplasm to popliteal lymph nodes
- Metastatic malignant neoplasm to superficial inguinal lymph nodes
- Metastatic malignant neoplasm to thigh
- Metastatic malignant neoplasm to tibial lymph nodes
- Metastatic squamous cell carcinoma to lymph node
- Metastatic squamous cell carcinoma to lymph node of lower limb
- Neoplasm of femoral lymph nodes
- Neoplasm of popliteal lymph nodes
- Neoplasm of superficial inguinal lymph nodes
- Neoplasm of tibial lymph nodes
- Non-Hodgkin lymphoma of central nervous system metastatic to lymph node of lower limb
- Non-Hodgkin's lymphoma of central nervous system
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Table of NeoplasmsClinical
Anatomical sites in the Table of Neoplasms that reference this code family.
| Site | Malig. Primary | Malig. Secondary | Ca in situ | Benign | Uncertain | Unspec. |
|---|---|---|---|---|---|---|
| lymph, lymphatic channel NEC › gland (secondary) › Cloquet | – | C77.4 | – | D36.0 | D48.7 | D49.89 |
| lymph, lymphatic channel NEC › gland (secondary) › femoral | – | C77.4 | – | D36.0 | D48.7 | D49.89 |
| lymph, lymphatic channel NEC › gland (secondary) › groin | – | C77.4 | – | D36.0 | D48.7 | D49.89 |
| lymph, lymphatic channel NEC › gland (secondary) › inguina, inguinal | – | C77.4 | – | D36.0 | D48.7 | D49.89 |
| lymph, lymphatic channel NEC › gland (secondary) › leg | – | C77.4 | – | D36.0 | D48.7 | D49.89 |
| lymph, lymphatic channel NEC › gland (secondary) › limb | – | C77.4 | – | D36.0 | D48.7 | D49.89 |
| lymph, lymphatic channel NEC › gland (secondary) › limb › lower | – | C77.4 | – | D36.0 | D48.7 | D49.89 |
| lymph, lymphatic channel NEC › gland (secondary) › lower limb | – | C77.4 | – | D36.0 | D48.7 | D49.89 |
| lymph, lymphatic channel NEC › gland (secondary) › popliteal | – | C77.4 | – | D36.0 | D48.7 | D49.89 |
| lymph, lymphatic channel NEC › gland (secondary) › Rosenmuller's | – | C77.4 | – | D36.0 | D48.7 | D49.89 |
| lymph, lymphatic channel NEC › gland (secondary) › subinguinal | – | C77.4 | – | D36.0 | D48.7 | D49.89 |
| lymph, lymphatic channel NEC › gland (secondary) › tibial | – | C77.4 | – | D36.0 | D48.7 | D49.89 |
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Convert C77.4 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C77.4Overview
Is C77.4 (Secondary and unspecified malignant neoplasm of lymph nodes) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report secondary and unspecified malignant neoplasm of inguinal and lower limb lymph nodes on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does C77.4 group to?
When secondary and unspecified malignant neoplasm of inguinal and lower limb lymph nodes is the principal diagnosis on an inpatient stay, it groups to MS-DRG 820, 821, 822, 823, 824, 825, 840, 841, 842, with relative weights from 1.0104 to 5.8648 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of C77.4?
Under the General Equivalence Mappings, secondary and unspecified malignant neoplasm of inguinal and lower limb lymph nodes converts to ICD-9-CM 196.5 (mal neo lymph-inguin/leg). The mapping is a direct match.
Footnotes
[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:
- The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
- The condition places limitations on self-care, independent living, and social interactions.
