C56.2
BillableMalignant neoplasm of left ovary
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C56.2 an HCC code?
Yes. C56.2 maps to Colorectal, Bladder, and Other Cancers under the CMS-HCC V28 risk adjustment model (and Lymphoma and Other Cancers under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for C56.2
For C56.2 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- 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
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed C56.2 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C56.2 is the ICD-10-CM diagnosis code for malignant neoplasm of left ovary. This code represents cancer that has started in the left ovary, one of the two female reproductive organs that produce eggs. It is used when a malignant (cancerous) tumor is confirmed to be located specifically on the left side. C56.2 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of female genital organs (c51-c58).
Under the CMS-HCC V28 risk adjustment model, C56.2 maps to Colorectal, Bladder, and Other Cancers (HCC 22) with a community, non-dual, aged base RAF weight of 0.000. Under the older CMS-HCC V24 model, C56.2 maps to Lymphoma and Other Cancers (HCC 10) with a community, non-dual, aged base RAF weight of 0.675. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Ensure laterality is documented in the medical record before assigning this code; if the ovary is not specified as left, right, or bilateral, query the physician for clarification. Because C56.2 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. 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, RAF weights, and MEAT documentation criteria for C56.2 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Ensure laterality is documented in the medical record before assigning this code; if the ovary is not specified as left, right, or bilateral, query the physician for clarification
- •This code should be used in conjunction with histology codes (C80.1 series) to specify the type of ovarian cancer (such as serous, mucinous, or clear cell carcinoma) when available
Clinical Significance
Malignant neoplasm of the left ovary carries the same clinical gravity as right-sided disease. Ovarian cancer treatment typically includes surgical staging with total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, and peritoneal biopsies, followed by platinum-based chemotherapy. Laterality documentation is essential for surgical planning and cancer registry accuracy.
Documentation Requirements
- ✓Laterality confirmed as left ovary
- ✓Histological type and grade
- ✓FIGO staging
- ✓Peritoneal cytology and peritoneal spread assessment
- ✓Lymph node status (pelvic and para-aortic)
- ✓Tumor marker levels (CA-125)
- ✓BRCA/genetic testing results
- ✓Residual disease status after surgery
Commonly Confused Codes
- •C56.1 — Right ovary; laterality reversal error
- •C56.3 — Bilateral ovaries; use when both sides are confirmed malignant
- •C56.9 — Unspecified ovary; use only when laterality cannot be determined
- •C79.62 — Secondary malignant neoplasm of ovary; metastatic disease to the ovary from another primary
- •D27.1 — Benign neoplasm of left ovary; verify malignancy before assigning cancer code