2027 ICD-10-CM Diagnosis Code C79.00Secondary malignant neoplasm of unspecified kidney and renal pelvis
ICD-10-CM Codes›C00–D49›C76-C80›C79
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 17
- Chronic Condition
C79.00 is a billable ICD-10-CM diagnosis code for secondary malignant neoplasm of unspecified kidney and renal pelvis. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 656 through 658, 686 through 688. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 25 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Secondary malignancies.
For Medicare Advantage risk adjustment, C79.00 maps to CMS-HCC Category 17 (Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic) under the V28 model, adding a risk factor of about 4.209 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
C79.00 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.
Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Carcinoma of renal pelvis
- Chromophobe renal cell carcinoma
- Cystadenocarcinoma of kidney
- Leukemic infiltrate of kidney
- Lymphomatous infiltrate of kidney
- Malignant lymphoma of kidney
- Malignant melanoma metastatic to kidney
- Metastatic chromophobe renal cell carcinoma
- Metastatic cystadenocarcinoma to kidney
- Metastatic malignant neoplasm to kidney
- Metastatic malignant neoplasm to renal pelvis
- Metastatic MiT family translocation renal cell carcinoma
- Metastatic papillary cystadenocarcinoma to kidney
- Metastatic papillary renal cell carcinoma
- Metastatic renal cell carcinoma
- Metastatic small cell neuroendocrine carcinoma
- Metastatic transitional cell carcinoma to kidney
- Metastatic transitional cell carcinoma to renal pelvis
- Metastatic transitional cell carcinoma to upper urinary tract
- MiT family translocation renal cell carcinoma
- Papillary cystadenocarcinoma of kidney
- Papillary renal cell carcinoma
- Secondary adenocarcinoma of kidney
- Secondary undifferentiated large cell malignant neoplasm of kidney
- Small cell carcinoma metastatic to kidney
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to C79.00: its own notes plus those printed at C79 and Chapter 2. A note printed at a category, block or chapter applies to every code under it.
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
Notes
General instructions on how these codes are used.
- Functional activity
- All neoplasms are classified in this chapter, whether they are functionally active or not. An additional code from Chapter 4 may be used, to identify functional activity associated with any neoplasm.
- Morphology [Histology]
- Chapter 2 classifies neoplasms primarily by site (topography), with broad groupings for behavior, malignant, in situ, benign, etc. The Table of Neoplasms should be used to identify the correct topography code. In a few cases, such as for malignant melanoma and certain neuroendocrine tumors, the morphology (histologic type) is included in the category and codes.
- Primary malignant neoplasms overlapping site boundaries
- A primary malignant neoplasm that overlaps two or more contiguous (next to each other) sites should be classified to the subcategory/code .8 ('overlapping lesion'), unless the combination is specifically indexed elsewhere. For multiple neoplasms of the same site that are not contiguous, such as tumors in different quadrants of the same breast, codes for each site should be assigned.
- Malignant neoplasm of ectopic tissue
- Malignant neoplasms of ectopic tissue are to be coded to the site mentioned, e.g., ectopic pancreatic malignant neoplasms are coded to pancreas, unspecified (C25.9).
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name C79.00, its category, or a range that includes it.
Applicable To 2
These notes mention C79.00.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Metastatic Malignant Neoplasm in the Kidney
the spread of a malignant neoplasm to the kidney. this may be from a primary kidney malignant neoplasm involving the opposite kidney, or from a malignant neoplasm at a distant site.
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. |
|---|---|---|---|---|---|---|
| calyx, renal | C65. | C79.0 | D09.19 | D30.1 | D41.1 | D49.51 |
| junction › pelviureteric | C65. | C79.0 | D09.19 | D30.1 | D41.1 | D49.59 |
| kidney (parenchymal) | C64. | C79.0 | D09.19 | D30.0 | D41.0 | D49.51 |
| kidney (parenchymal) › calyx | C65. | C79.0 | D09.19 | D30.1 | D41.1 | D49.51 |
| kidney (parenchymal) › hilus | C65. | C79.0 | D09.19 | D30.1 | D41.1 | D49.51 |
| kidney (parenchymal) › pelvis | C65. | C79.0 | D09.19 | D30.1 | D41.1 | D49.51 |
| parenchyma, kidney | C64. | C79.0 | D09.19 | D30.0 | D41.0 | D49.51 |
| pelvis, pelvic › renal | C65. | C79.0 | D09.19 | D30.1 | D41.1 | D49.51 |
| renal | C64. | C79.0 | D09.19 | D30.0 | D41.0 | D49.51 |
| renal › calyx | C65. | C79.0 | D09.19 | D30.1 | D41.1 | D49.51 |
| renal › hilus | C65. | C79.0 | D09.19 | D30.1 | D41.1 | D49.51 |
| renal › parenchyma | C64. | C79.0 | D09.19 | D30.0 | D41.0 | D49.51 |
| renal › pelvis | C65. | C79.0 | D09.19 | D30.1 | D41.1 | D49.51 |
Patient EducationClinical
Kidney Cancer
You have two kidneys. They are fist-sized organs on either side of your backbone above your waist. The tubes inside filter and clean your blood, taking out waste products and making urine. Kidney cancer forms in the lining of tiny tubes inside your kidneys.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert C79.00 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C79.00Overview
What is the ICD-10 code for secondary malignant neoplasm of unspecified kidney and renal pelvis?
The ICD-10-CM code for secondary malignant neoplasm of unspecified kidney and renal pelvis is C79.00 (sometimes written as C7900). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is C79.00 (Secondary malignant neoplasm of kidney and renal pelvis) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report secondary malignant neoplasm of unspecified kidney and renal pelvis on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does C79.00 group to?
When secondary malignant neoplasm of unspecified kidney and renal pelvis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 656, 687, 658, 657, 686, 688, with relative weights from 0.7332 to 3.2782 depending on complications. Higher weights mean higher Medicare reimbursement.
Is C79.00 a CC or MCC?
CMS lists C79.00 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 25 closely related codes in its exclusion list.
Can C79.00 be reported with a code from C7B?
Not as a rule. The Excludes1 note at C79, which applies to C79.00, lists "secondary carcinoid tumors (C7B.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
What HCC is C79.00?
C79.00 (secondary malignant neoplasm of unspecified kidney and renal pelvis) maps to CMS-HCC Category 17 (Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic), commonly written as HCC 17, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 8 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 17.
Does C79.00 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, C79.00 adds a risk adjustment factor of about 4.209 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 1.952 to 4.235 depending on the payment segment). HCC 17 sits at the top of its hierarchy, so no other condition category supersedes it. See the full factor table on the HCC 17 category page.
