What is ICD-10 code C75.1?

C75.1 is the ICD-10-CM diagnosis code for Malignant neoplasm of pituitary gland. Cancer that starts in the pituitary gland, a small gland at the base of the brain that controls many hormones in the body. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). C75.1 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C75.1 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. C75.1 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. C75.1 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for C75.1?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. For C75.1, V28 maps to Lung and Other Severe Cancers at RAF 1.136 while V24 mapped to Lymphoma and Other Cancers at RAF 0.675. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting C75.1?

Pituitary carcinomas are extremely rare; confirm malignant diagnosis and distinguish from benign pituitary adenomas in documentation Document any functional status (hormone-secreting vs. non-secreting) as this impacts clinical management and may require additional codes Because C75.1 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

2026 ICD-10-CM C75.1: Malignant neoplasm

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupC75.1Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of thyroid and other endocrine glands (C73-C75)

C75.1

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Malignant neoplasm of pituitary gland

Cancer that starts in the pituitary gland, a small gland at the base of the brain that controls many hormones in the body.

Buddy Insight

Malignant neoplasm of the pituitary gland represents pituitary carcinoma, which is defined by the presence of craniospinal or systemic metastases.

CMS-HCC V28

Mapped

HCC 20

Lung and Other Severe Cancers

RAF 1.136

CMS-HCC V24

Mapped

HCC 10

Lymphoma and Other Cancers

RAF 0.675

ACA/HHS

Mapped

HCC 9

HHS-HCC 9

Varies by metal level

ESRD/PACE

Mapped

HCC 10

Lymphoma and Other Cancers

RAF 0.111

RXHCC

Mapped

HCC 22

Cancer, Other Specified Sites

RAF 0.124

Code Book Path

Official

C75Malignant neoplasm of other endocrine glands and related structures

C75.1Malignant neoplasm of pituitary gland

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for C75.1 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C75.1 in this effective period.

Related Child Codes

Official

C75.0Malignant neoplasm of parathyroid gland

C75.2Malignant neoplasm of craniopharyngeal duct

C75.3Malignant neoplasm of pineal gland

C75.4Malignant neoplasm of carotid body

C75.5Malignant neoplasm of aortic body and other paraganglia

Includes

Official

ICD-10-CM does not list Includes notes for C75.1 in this effective period.

Excludes 1

Official

malignant carcinoid tumors (C7A.0-)
malignant neoplasm of adrenal gland (C74.-)
malignant neoplasm of endocrine pancreas (C25.4)
malignant neoplasm of islets of Langerhans (C25.4)
malignant neoplasm of ovary (C56.-)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C75.1 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for C75.1 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for C75.1 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Pathology confirming pituitary carcinoma with evidence of metastatic disease (defining criterion)

Documentation of hormonal hypersecretion or hypopituitarism

Imaging showing sellar/suprasellar mass and any metastatic disease

Visual field assessment results

MEAT Support

HCC Buddy guidance

Pathology confirming pituitary carcinoma with evidence of metastatic disease (defining criterion)

Documentation of hormonal hypersecretion or hypopituitarism

Imaging showing sellar/suprasellar mass and any metastatic disease

Visual field assessment results

Audit Caution

HCC Buddy guidance

Coding pituitary adenoma (benign) as pituitary carcinoma — this is a major coding error given the extreme rarity of pituitary carcinoma

Confusing 'invasive' pituitary adenoma with pituitary carcinoma — invasion alone does not define malignancy; metastasis is required

Not coding associated endocrine disorders (hypopituitarism, acromegaly, Cushing disease) separately

Failing to verify metastatic disease documentation which defines pituitary carcinoma

Common Mistakes

HCC Buddy guidance

D35.2 — Benign neoplasm of pituitary gland: Pituitary adenomas are benign and vastly more common than carcinoma

D44.3 — Neoplasm of uncertain behavior of pituitary gland: Use when malignancy is not confirmed

E22.0 — Acromegaly and pituitary gigantism: Hormonal condition from growth hormone excess, usually from benign adenoma

E23.0 — Hypopituitarism: May result from pituitary tumor but is a separate endocrine condition

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is C75.1 an HCC code?

Yes. C75.1 (Malignant neoplasm of pituitary gland) maps to Lung and Other Severe Cancers under the CMS-HCC V28 risk adjustment model (and Lymphoma and Other Cancers under V24), with a community non-dual aged RAF of 1.136. It is billable for payment year 2026.

Coder answer: C75.1 is billable and maps to V28 HCC 20, Lung and Other Severe Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: C75.1
Description: Malignant neoplasm of pituitary gland
HCC (V28): HCC 20 — Lung and Other Severe Cancers
RAF: 1.136
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 20, Lung and Other Severe Cancers

1.136

V24HCC 10, Lymphoma and Other Cancers

0.675

ESRDHCC 10, Lymphoma and Other Cancers

0.111

RxHCCHCC 22, Cancer, Other Specified Sites

0.124

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. 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.

Work C75.1 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for C75.1

For C75.1 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 C75.1 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

Get the V28 RAF + MEAT cheat sheet

One printable page: confirm a code's V28 HCC status, its RAF weight, and the MEAT your note needs to make it stick. Free, no card.

Free PDF. No card. Unsubscribe anytime.

What This Code Means

C75.1 is the ICD-10-CM diagnosis code for malignant neoplasm of pituitary gland. Cancer that starts in the pituitary gland, a small gland at the base of the brain that controls many hormones in the body. C75.1 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, C75.1 maps to Lung and Other Severe Cancers (HCC 20) with a community, non-dual, aged base RAF weight of 1.136. Under the older CMS-HCC V24 model, C75.1 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.

Pituitary carcinomas are extremely rare; confirm malignant diagnosis and distinguish from benign pituitary adenomas in documentation. Because C75.1 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 C75.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Pituitary carcinomas are extremely rare; confirm malignant diagnosis and distinguish from benign pituitary adenomas in documentation
•Document any functional status (hormone-secreting vs. non-secreting) as this impacts clinical management and may require additional codes

Clinical Significance

Malignant neoplasm of the pituitary gland represents pituitary carcinoma, which is defined by the presence of craniospinal or systemic metastases. This is extremely rare — most pituitary tumors are benign adenomas. Pituitary carcinoma causes hormonal imbalances and may compress the optic chiasm, causing visual field defects. Accurate coding is essential to distinguish this from the much more common benign pituitary adenoma.

Documentation Requirements

✓Pathology confirming pituitary carcinoma with evidence of metastatic disease (defining criterion)
✓Documentation of hormonal hypersecretion or hypopituitarism
✓Imaging showing sellar/suprasellar mass and any metastatic disease
✓Visual field assessment results
✓Current treatment status (surgery, radiation, medical therapy)

Commonly Confused Codes

•D35.2: Benign neoplasm of pituitary gland: Pituitary adenomas are benign and vastly more common than carcinoma
•D44.3: Neoplasm of uncertain behavior of pituitary gland: Use when malignancy is not confirmed
•E22.0: Acromegaly and pituitary gigantism: Hormonal condition from growth hormone excess, usually from benign adenoma
•E23.0: Hypopituitarism: May result from pituitary tumor but is a separate endocrine condition
•C75.2: Malignant neoplasm of craniopharyngeal duct: Adjacent sellar region tumor with different origin