C75.9
BillableMalignant neoplasm of endocrine gland, unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C75.9 an HCC code?
Yes. C75.9 maps to Melanoma and Other Skin Cancers under the CMS-HCC V28 risk adjustment model (and Breast, Prostate, and Other Cancers and Tumors 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 C75.9
For C75.9 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 C75.9 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C75.9 is the ICD-10-CM diagnosis code for malignant neoplasm of endocrine gland, unspecified. A malignant (cancerous) tumor of an endocrine gland where the specific gland involved has not been identified or documented. C75.9 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, C75.9 maps to Melanoma and Other Skin Cancers (HCC 23) with a community, non-dual, aged base RAF weight of 0.251. Under the older CMS-HCC V24 model, C75.9 maps to Breast, Prostate, and Other Cancers and Tumors (HCC 12) with a community, non-dual, aged base RAF weight of 0.150. 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.
This is a default code used when endocrine malignancy is confirmed but the specific gland is unspecified. Because C75.9 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 C75.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is a default code used when endocrine malignancy is confirmed but the specific gland is unspecified
- •Query the provider for more specific anatomical location to assign a more precise code
Clinical Significance
Malignant neoplasm of endocrine gland, unspecified, is used when endocrine gland cancer is documented but the specific gland cannot be identified. This is a nonspecific code that should prompt a thorough chart review and provider query, as virtually all endocrine malignancies can be coded to a specific gland with adequate documentation.
Documentation Requirements
- ✓Documentation confirming endocrine gland malignancy
- ✓Thorough review of imaging, pathology, and surgical notes to identify the specific gland
- ✓Provider query requesting identification of the affected endocrine gland
- ✓Hormonal evaluation that may help identify tissue of origin
- ✓Treatment status and management plan
Commonly Confused Codes
- •C73 — Malignant neoplasm of thyroid: Most common endocrine malignancy; verify it is not thyroid
- •C75.0-C75.8 — Specific endocrine gland malignancies: Use when the specific gland is identified
- •D44.9 — Neoplasm of uncertain behavior of unspecified endocrine gland: Use when malignancy is not confirmed
- •E34.9 — Endocrine disorder, unspecified: Endocrine dysfunction, not malignancy