C13.2
BillableMalignant neoplasm of posterior wall of hypopharynx
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C13.2 an HCC code?
Yes. C13.2 maps to Lymphoma and Other Cancers under the CMS-HCC V28 risk adjustment model (and Colorectal, Bladder, 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 C13.2
For C13.2to 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 C13.2 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C13.2 is the ICD-10-CM diagnosis code for malignant neoplasm of posterior wall of hypopharynx. This code describes cancer that starts in the back wall of the hypopharynx, which is the lower part of the throat located behind the larynx. This is a serious malignant tumor that requires immediate medical attention and treatment. C13.2 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of lip, oral cavity and pharynx (c00-c14).
Under the CMS-HCC V28 risk adjustment model, C13.2 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, C13.2 maps to Colorectal, Bladder, and Other Cancers (HCC 11) with a community, non-dual, aged base RAF weight of 0.307. 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.
Verify the specific site of the tumor is documented as the posterior (back) wall of the hypopharynx, as other hypopharyngeal sites have different codes (C13.0, C13.1, C13.3). Because C13.2 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 C13.2 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify the specific site of the tumor is documented as the posterior (back) wall of the hypopharynx, as other hypopharyngeal sites have different codes (C13.0, C13.1, C13.3)
- •Ensure documentation includes staging information and whether the cancer has metastasized, as this will affect treatment planning and may require additional codes for secondary sites
Clinical Significance
Malignant neoplasm of the posterior wall of the hypopharynx is a challenging cancer due to its proximity to the prevertebral fascia and cervical spine. Posterior wall tumors that invade the prevertebral fascia are generally considered unresectable, making precise depth of invasion documentation critical for treatment planning.
Documentation Requirements
- ✓Pathology-confirmed malignancy
- ✓Documentation specifying posterior wall of hypopharynx
- ✓Imaging assessment of prevertebral fascia involvement and cervical spine invasion
- ✓TNM staging with particular attention to T4 criteria (prevertebral fascia invasion)
- ✓Swallowing assessment and nutritional status
Commonly Confused Codes
- •C10.3 — Posterior wall of oropharynx; the hypopharynx is lower than the oropharynx — ensure correct pharyngeal level
- •C11.1 — Posterior wall of nasopharynx; the highest pharyngeal level — do not confuse with hypopharynx
- •C12 — Pyriform sinus; the pyriform sinus is lateral, the posterior wall is midline
- •C13.8 — Overlapping sites of hypopharynx; use when tumor extends from posterior wall to other hypopharyngeal sites