What is ICD-10 code E32.8?

E32.8 is the ICD-10-CM diagnosis code for Other diseases of thymus. Other diseases or conditions affecting the thymus gland not classified elsewhere, such as cysts, tumors, or atrophy. It belongs to the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89). E32.8 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. E32.8 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. E32.8 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. E32.8 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 E32.8?

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. E32.8 was a payment HCC under V24 (Other Significant Endocrine and Metabolic Disorders) but the V28 recalibration removed it from the risk adjustment model. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting E32.8?

Specify the type of thymus disease in documentation (cyst, tumor, atrophy, etc.) for clarity If a more specific thymus condition code exists, use that instead of this catch-all code Because E32.8 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.

E32.8: Other diseases of thymus — ICD-10 | Other Significant Endocrine and Metabolic Disorders

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 lookupE32.8Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Endocrine, nutritional and metabolic diseases (E00-E89) / Disorders of other endocrine glands (E20-E35)

E32.8

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

Other diseases of thymus

Other diseases or conditions affecting the thymus gland not classified elsewhere, such as cysts, tumors, or atrophy.

Buddy Insight

Other diseases of the thymus encompasses a range of thymic pathologies not classified elsewhere, including thymic cysts, thymic atrophy, and other non-neoplastic thymic disorders.

CMS-HCC V28

N/A

—

Not risk-adjusted for this model/period.

Not mapped

CMS-HCC V24

Mapped

HCC 23

Other Significant Endocrine a...

RAF 0.194

ACA/HHS

Mapped

HCC 30

HHS-HCC 30

Varies by metal level

ESRD/PACE

Mapped

HCC 23

Other Significant Endocrine a...

RAF 0.036

RXHCC

Mapped

HCC 43

Other Significant Endocrine a...

RAF 0.063

Code Book Path

Official

E32Diseases of thymus

E32.8Other diseases of thymus

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for E32.8 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for E32.8 in this effective period.

Related Child Codes

Official

E32.0Persistent hyperplasia of thymus

E32.1Abscess of thymus

E32.9Disease of thymus, unspecified

Includes

Official

ICD-10-CM does not list Includes notes for E32.8 in this effective period.

Excludes 1

Official

aplasia or hypoplasia with immunodeficiency (D82.1)
thymoma (D15.0)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for E32.8 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for E32.8 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for E32.8 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Documentation should specify the exact thymic condition (cyst, atrophy, ectopic thymus, fatty replacement, etc.) with supporting imaging or pathology findings.

The provider must document clinical relevance, including any immune dysfunction or symptoms attributable to the thymic disease.

Size measurements and comparison with prior imaging should be included when available.

MEAT Support

HCC Buddy guidance

Documentation should specify the exact thymic condition (cyst, atrophy, ectopic thymus, fatty replacement, etc.) with supporting imaging or pathology findings.

The provider must document clinical relevance, including any immune dysfunction or symptoms attributable to the thymic disease.

Size measurements and comparison with prior imaging should be included when available.

Audit Caution

HCC Buddy guidance

Do not use this code for thymic neoplasms, which have specific neoplasm codes.

Avoid using this catch-all code when a more specific thymic condition code exists.

Thymic involution (normal age-related shrinkage) is a physiological process and should not be coded as a disease unless it is pathologically accelerated or symptomatic.

Common Mistakes

HCC Buddy guidance

E32.0 (Persistent hyperplasia of thymus) is specific to thymic enlargement.

E32.1 (Abscess of thymus) covers infectious thymic pathology.

E32.9 (Disease of thymus, unspecified) should only be used when the specific thymic disease cannot be determined.

C37 (Malignant neoplasm of thymus) and D15.0 (Benign neoplasm of thymus) cover neoplastic thymic conditions.

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is E32.8 an HCC code?

Yes. E32.8 maps to Other Significant Endocrine and Metabolic Disorders under the V24 model but is not retained in V28.

HCC Category Mapping

V24HCC 23, Other Significant Endocrine and Metabolic Disorders

0.194

ESRDHCC 23, Other Significant Endocrine and Metabolic Disorders

0.036

RxHCCHCC 43, Other Significant Endocrine and Metabolic Disorders

0.063

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 E32.8 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for E32.8

For E32.8to 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 E32.8 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

E32.8 is the ICD-10-CM diagnosis code for other diseases of thymus. Other diseases or conditions affecting the thymus gland not classified elsewhere, such as cysts, tumors, or atrophy. E32.8 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering disorders of other endocrine glands (e20-e35).

Under the older CMS-HCC V24 model, E32.8 maps to Other Significant Endocrine and Metabolic Disorders (HCC 23) with a community, non-dual, aged base RAF weight of 0.194. 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.

Specify the type of thymus disease in documentation (cyst, tumor, atrophy, etc.) for clarity. Because E32.8 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 E32.8 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Specify the type of thymus disease in documentation (cyst, tumor, atrophy, etc.) for clarity
•If a more specific thymus condition code exists, use that instead of this catch-all code

Clinical Significance

Other diseases of the thymus encompasses a range of thymic pathologies not classified elsewhere, including thymic cysts, thymic atrophy, and other non-neoplastic thymic disorders. These conditions may affect immune function since the thymus plays a central role in T-cell maturation, particularly relevant in pediatric patients or immunocompromised adults.

Documentation Requirements

✓Documentation should specify the exact thymic condition (cyst, atrophy, ectopic thymus, fatty replacement, etc.) with supporting imaging or pathology findings.
✓The provider must document clinical relevance, including any immune dysfunction or symptoms attributable to the thymic disease.
✓Size measurements and comparison with prior imaging should be included when available.

Excludes 1, Do NOT code together

aplasia or hypoplasia with immunodeficiency (D82.1)
thymoma (D15.0)

Commonly Confused Codes

•E32.0 (Persistent hyperplasia of thymus) is specific to thymic enlargement.
•E32.1 (Abscess of thymus) covers infectious thymic pathology.
•E32.9 (Disease of thymus, unspecified) should only be used when the specific thymic disease cannot be determined.
•C37 (Malignant neoplasm of thymus) and D15.0 (Benign neoplasm of thymus) cover neoplastic thymic conditions.