2027 ICD-10-CM Diagnosis Code C56.3Malignant neoplasm of bilateral ovaries
ICD-10-CM Codes›C00–D49›C51-C58›C56
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 22
- Chronic Condition
C56.3 is a billable ICD-10-CM diagnosis code for malignant neoplasm of bilateral ovaries. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 731 through 733, 754 through 756. 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 27 closely related codes. Coders also document this condition as bilateral neoplasm of uncertain behavior of ovaries. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Female reproductive system cancers - ovary.
For Medicare Advantage risk adjustment, C56.3 maps to CMS-HCC Category 22 (Bladder, Colorectal, and Other Cancers) under the V28 model, adding a risk factor of about 0.363 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
C56.3 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.
- Bilateral neoplasm of uncertain behavior of ovaries
- Left ovarian serous cystadenoma of borderline malignancy
- Neoplasm of uncertain behavior of left ovary
- Neoplasm of uncertain behavior of right ovary
- Right ovarian serous cystadenoma of borderline malignancy
- Serous cystadenoma borderline malignancy of ovary
- Serous cystadenoma of borderline malignancy of bilateral ovaries
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to C56.3: its own notes plus those printed at C56, block C51-C58, and Chapter 2. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- malignant neoplasm of skin of female genital organs
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify any functional activity
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 C56.3, its category, or a range that includes it.
Applicable To 2
These notes mention C56.3.
Excludes1 1
These codes carry an Excludes1 note naming C56.3: they are not reported together with it, unless the two conditions are unrelated.
Code First 2
These codes say to code first a condition named in the note, and C56.3 is one of the conditions named.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Malignant Ovarian Neoplasm
a primary or metastatic malignant neoplasm involving the ovary. most primary malignant ovarian neoplasms are either carcinomas (serous, mucinous, or endometrioid adenocarcinomas) or malignant germ cell tumors. metastatic malignant neoplasms to the ovary include carcinomas, lymphomas, and melanomas.
Patient EducationClinical
Ovarian Cancer
Cancer is a disease in which abnormal cells in the body grow out of control and form a tumor. Ovarian cancer is a cancerous tumor that forms in the tissues of an ovary. The ovaries are a pair of female reproductive glands that make eggs and female hormones.
The full article covers:
- What is ovarian cancer?
- What are the types of ovarian cancer?
- What causes ovarian cancer?
- Who is more likely to develop ovarian cancer?
- What are the symptoms of ovarian cancer?
- How is ovarian cancer diagnosed?
- What are the treatments for ovarian cancer?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Code History & ChangesHistory
Replacement C56.3 replaces the following previously assigned code(s):
- C56.1 - Malignant neoplasm of right ovary
- C56.2 - Malignant neoplasm of left ovary
Questions About C56.3Overview
What is the ICD-10 code for malignant neoplasm of bilateral ovaries?
The ICD-10-CM code for malignant neoplasm of bilateral ovaries is C56.3 (sometimes written as C563). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is C56.3 (Malignant neoplasm of ovary) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of bilateral ovaries on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does C56.3 group to?
When malignant neoplasm of bilateral ovaries is the principal diagnosis on an inpatient stay, it groups to MS-DRG 732, 755, 756, 754, 733, 731, with relative weights from 0.8583 to 3.5462 depending on complications. Higher weights mean higher Medicare reimbursement.
Is C56.3 a CC or MCC?
CMS lists C56.3 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 27 closely related codes in its exclusion list.
Does C56.3 need an additional code?
When the condition applies, yes. The Use Additional Code note at C56, which applies to C56.3, reads: code to identify any functional activity. The additional code is reported after C56.3.
What HCC is C56.3?
C56.3 (malignant neoplasm of bilateral ovaries) maps to CMS-HCC Category 22 (Bladder, Colorectal, and Other Cancers), commonly written as HCC 22, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 10 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 22.
Does C56.3 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, C56.3 adds a risk adjustment factor of about 0.363 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.314 to 0.410 depending on the payment segment). A more severe related category (HCC 17, HCC 18, HCC 19, HCC 20, and HCC 21) supersedes it when both are reported. See the full factor table on the HCC 22 category page.
