What is ICD-10 code E32.0?

E32.0 is the ICD-10-CM diagnosis code for Persistent hyperplasia of thymus. A condition where the thymus gland, which is normally present in children, persists and remains enlarged into adulthood. It belongs to the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89). E32.0 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. E32.0 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. E32.0 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. E32.0 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 E32.0?

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. E32.0 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 E32.0?

This condition is often asymptomatic and discovered incidentally on imaging Document whether the patient is symptomatic or if this is an incidental finding Because E32.0 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.

E32.0: Persistent hyperplasia of thymus — ICD-10 | Other Significant Endocrine and Metabolic

ICD-10-CM Code View

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Code lookupE32.0Effective 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)

E32.0

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

Persistent hyperplasia of thymus

A condition where the thymus gland, which is normally present in children, persists and remains enlarged into adulthood.

Buddy Insight

Persistent hyperplasia of the thymus represents an abnormal enlargement of the thymus gland that persists beyond the normal age of involution, which typically occurs during puberty.

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

E32.0Persistent hyperplasia of thymus

Inclusion Terms

Official

Hypertrophy of thymus

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for E32.0 in this effective period.

Related Child Codes

Official

E32.1Abscess of thymus

E32.8Other diseases of thymus

E32.9Disease of thymus, unspecified

Includes

Official

ICD-10-CM does not list Includes notes for E32.0 in this effective period.

Excludes 1

Official

aplasia or hypoplasia of thymus with immunodeficiency (D82.1)
myasthenia gravis (G70.0)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for E32.0 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for E32.0 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for E32.0 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Documentation should include imaging findings (computed tomography or magnetic resonance imaging) demonstrating thymic enlargement with measurements, patient age, and whether symptoms are present.

The provider should note any associated autoimmune conditions, particularly myasthenia gravis.

Pathology results from biopsy should be documented if performed to rule out thymoma or lymphoma.

MEAT Support

HCC Buddy guidance

Documentation should include imaging findings (computed tomography or magnetic resonance imaging) demonstrating thymic enlargement with measurements, patient age, and whether symptoms are present.

The provider should note any associated autoimmune conditions, particularly myasthenia gravis.

Pathology results from biopsy should be documented if performed to rule out thymoma or lymphoma.

Audit Caution

HCC Buddy guidance

Do not confuse thymic hyperplasia with thymoma, which requires a neoplasm code.

Thymic rebound hyperplasia after chemotherapy or stress is a distinct entity that may also use this code but should be clearly documented.

Ensure imaging or pathology supports the diagnosis rather than coding based solely on an incidental finding without clinical correlation.

Common Mistakes

HCC Buddy guidance

C37 (Malignant neoplasm of thymus) should be used when malignancy is confirmed.

D15.0 (Benign neoplasm of thymus) is appropriate for thymoma without malignancy.

E32.8 (Other diseases of thymus) covers other thymic conditions not classified as hyperplasia.

G70.00/G70.01 (Myasthenia gravis) should be coded additionally if that condition is also present.

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 E32.0 an HCC code?

Yes. E32.0 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 E32.0 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for E32.0

For E32.0to 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 E32.0 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

E32.0 is the ICD-10-CM diagnosis code for persistent hyperplasia of thymus. A condition where the thymus gland, which is normally present in children, persists and remains enlarged into adulthood. E32.0 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, E32.0 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.

This condition is often asymptomatic and discovered incidentally on imaging. Because E32.0 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 E32.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This condition is often asymptomatic and discovered incidentally on imaging
•Document whether the patient is symptomatic or if this is an incidental finding

Clinical Significance

Persistent hyperplasia of the thymus represents an abnormal enlargement of the thymus gland that persists beyond the normal age of involution, which typically occurs during puberty. This condition can be associated with autoimmune disorders such as myasthenia gravis and may indicate underlying immune dysregulation requiring ongoing monitoring.

Documentation Requirements

✓Documentation should include imaging findings (computed tomography or magnetic resonance imaging) demonstrating thymic enlargement with measurements, patient age, and whether symptoms are present.
✓The provider should note any associated autoimmune conditions, particularly myasthenia gravis.
✓Pathology results from biopsy should be documented if performed to rule out thymoma or lymphoma.

Commonly Confused Codes

•C37 (Malignant neoplasm of thymus) should be used when malignancy is confirmed.
•D15.0 (Benign neoplasm of thymus) is appropriate for thymoma without malignancy.
•E32.8 (Other diseases of thymus) covers other thymic conditions not classified as hyperplasia.
•G70.00/G70.01 (Myasthenia gravis) should be coded additionally if that condition is also present.