C74.91
BillableMalignant neoplasm of unspecified part of right adrenal gland
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C74.91 an HCC code?
Yes. C74.91 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 C74.91
For C74.91 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 C74.91 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C74.91 is the ICD-10-CM diagnosis code for malignant neoplasm of unspecified part of right adrenal gland. This code describes cancer that has developed in the right adrenal gland (a small hormone-producing gland that sits on top of the kidney), but the specific location within the gland has not been identified. The cancer cells are malignant, meaning they can spread to other parts of the body. C74.91 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of thyroid and other endocrine glands (c73-c75).
Under the CMS-HCC V28 risk adjustment model, C74.91 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, C74.91 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.
Use this code only when the documentation does not specify which part of the right adrenal gland is affected; if a specific location is documented (such as cortex or medulla), use the more specific code instead. Because C74.91 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 C74.91 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code only when the documentation does not specify which part of the right adrenal gland is affected; if a specific location is documented (such as cortex or medulla), use the more specific code instead
- •Ensure laterality is clearly documented as 'right' before assigning this code; verify the distinction between C74.01 (cortex), C74.02 (medulla), and C74.91 (unspecified part) based on pathology or imaging reports
Clinical Significance
Malignant neoplasm of unspecified part of the right adrenal gland provides laterality but lacks compartment specification (cortex vs. medulla). This intermediate specificity code is appropriate when documentation confirms right-sided adrenal cancer but pathology does not clarify whether the tumor originated in the cortex or medulla.
Documentation Requirements
- ✓Documentation confirming right-sided adrenal malignancy
- ✓Pathology report — attempt to determine cortex vs. medulla origin
- ✓Hormonal evaluation (cortisol/androgens suggest cortex; catecholamines suggest medulla)
- ✓Staging information
- ✓Treatment status and management plan
Commonly Confused Codes
- •C74.01 — Right adrenal cortex: Use when cortex origin is confirmed
- •C74.11 — Right adrenal medulla: Use when medulla origin is confirmed
- •C74.92 — Left adrenal, unspecified part: Laterality error; verify right side
- •C74.90 — Unspecified part, unspecified side: Use C74.91 when right side is documented
- •C79.71 — Secondary malignant neoplasm of right adrenal gland: Metastatic, not primary