2026 ICD-10-CM Diagnosis Code E24.1Nelson's syndrome

ICD-10-CM Codes›E00–E89›E20-E35›E24

ICD-10-CM E24.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

E24.1 is a billable ICD-10-CM diagnosis code for Nelson's syndrome. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 643 through 645. Coders also document this condition as ACTH-dependent Cushing's syndrome. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified endocrine disorders.

Code Identity

ICD-10-CM Code
E24.1
Billable Status
Yes — Valid for Submission
Code Describes
Nelson's syndrome
Short Description
Nelson's syndrome
Same as the full description in the CMS dataset.
Parent Code
E24
Cushing's syndrome

Code Classification

ChapterE00–E89Endocrine, nutritional and metabolic diseases
SectionE20-E35Disorders of other endocrine glands
CategoryE24Cushing's syndrome
This CodeE24.1Nelson's syndrome

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • ACTH-dependent Cushing's syndrome
  • Nelson syndrome

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Nelson's syndrome

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR END015
Other specified and unspecified endocrine disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Nelson Syndrome

    a syndrome characterized by hyperpigmentation, enlarging pituitary mass, visual defects secondary to compression of the optic chiasm, and elevated serum acth. it is caused by the expansion of an underlying acth-secreting pituitary adenoma that grows in the absence of feedback inhibition by adrenal corticosteroids, usually after adrenalectomy.

  • Nelson Syndrome

    a syndrome that develops following bilateral adrenalectomy for cushing syndrome. the signs and symptoms result from the presence of an adenocorticotropin-secreting pituitary gland adenoma, and include enlargement of the sella turcica and pressure on the adjacent structures, and skin hyperpigmentation.

Patient EducationClinical

Pituitary Disorders

Your pituitary gland is a pea-sized gland at the base of your brain. The pituitary is the "master control gland" - it makes hormones that affect growth and the functions of other glands in the body.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert E24.1 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
253.8 Pituitary disorder NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About E24.1Overview

Is E24.1 (Cushing's syndrome) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report Nelson's syndrome on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does E24.1 group to?

When Nelson's syndrome is the principal diagnosis on an inpatient stay, it groups to MS-DRG 643, 644, 645, with relative weights from 0.7683 to 1.6461 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of E24.1?

Under the General Equivalence Mappings, Nelson's syndrome converts to ICD-9-CM 253.8 (pituitary disorder NEC). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.