C71.3
BillableMalignant neoplasm of parietal lobe
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C71.3 an HCC code?
Yes. C71.3 maps to Lung and Other Severe 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 C71.3
For C71.3 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 C71.3 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C71.3 is the ICD-10-CM diagnosis code for malignant neoplasm of parietal lobe. Cancer that develops in the parietal lobe of the brain, which controls sensation and spatial awareness. This is a malignant brain tumor in the upper middle-back part of the cerebrum. C71.3 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of eye, brain and other parts of central nervous system (c69-c72).
Under the CMS-HCC V28 risk adjustment model, C71.3 maps to Lung and Other Severe Cancers (HCC 20) with a community, non-dual, aged base RAF weight of 0.000. Under the older CMS-HCC V24 model, C71.3 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.
Verify parietal lobe location is documented to avoid confusion with adjacent lobes. Because C71.3 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 C71.3 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify parietal lobe location is documented to avoid confusion with adjacent lobes
- •Note laterality when specified, as this affects neurological deficits and treatment approach
Clinical Significance
Parietal lobe malignancy affects the brain region responsible for somatosensory processing, spatial awareness, and proprioception. Tumors here can cause contralateral sensory loss, spatial neglect (particularly with right parietal involvement), apraxia, and agraphia. Accurate localization is essential for neurosurgical planning to minimize postoperative deficits.
Documentation Requirements
- ✓Pathology confirming malignancy with histological type and World Health Organization grade
- ✓MRI brain documenting parietal lobe location
- ✓Laterality (right versus left) — clinically important for predicting deficits
- ✓Assessment of sensory function, spatial awareness, and hand coordination
- ✓Molecular markers and treatment approach