C7A.091
BillableMalignant carcinoid tumor of the thymus
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C7A.091 an HCC code?
Yes. C7A.091 maps to Lymphoma and Other 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 C7A.091
For C7A.091to 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 C7A.091 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C7A.091 is the ICD-10-CM diagnosis code for malignant carcinoid tumor of the thymus. A rare cancer that develops from hormone-producing cells in the thymus gland, located in the chest behind the breastbone. C7A.091 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neuroendocrine tumors (c7a).
Under the CMS-HCC V28 risk adjustment model, C7A.091 maps to Lymphoma and Other Cancers (HCC 21) with a community, non-dual, aged base RAF weight of 0.671. Under the older CMS-HCC V24 model, C7A.091 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.
Thymic carcinoid tumors are uncommon; ensure documentation distinguishes this from thymoma or other thymic malignancies. Because C7A.091 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 C7A.091 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Thymic carcinoid tumors are uncommon; ensure documentation distinguishes this from thymoma or other thymic malignancies
- •Consider associated conditions like MEN syndromes, which may require additional coding
Clinical Significance
Malignant carcinoid tumor of the thymus is an extremely rare neuroendocrine malignancy arising from the thymus gland in the anterior mediastinum. Thymic carcinoids are more aggressive than typical carcinoid tumors and have a higher rate of local invasion and metastasis. They are frequently associated with Multiple Endocrine Neoplasia type 1 (MEN1) syndrome, requiring screening for associated endocrine tumors.
Documentation Requirements
- ✓Pathology report confirming neuroendocrine/carcinoid histology of the thymus
- ✓Distinction from thymoma, thymic carcinoma, or other anterior mediastinal tumors
- ✓Documentation of any associated MEN1 syndrome or other endocrine neoplasia syndromes
- ✓Tumor stage and grade
- ✓Treatment plan (surgical resection, chemotherapy, radiation)
- ✓Presence or absence of ectopic hormone production (Cushing syndrome from ACTH secretion)
Commonly Confused Codes
- •C37 — Malignant neoplasm of thymus: Use C37 for thymoma or thymic carcinoma (non-neuroendocrine); C7A.091 is specifically for carcinoid/neuroendocrine histology
- •C7A.090 — Malignant carcinoid tumor of the bronchus and lung: Anatomically adjacent but distinct; verify whether the tumor originates in the thymus versus the lung/bronchus
- •D3A.091 — Benign carcinoid tumor of the thymus: Use D3A.091 only if the tumor demonstrates benign behavior