2026 ICD-10-CM Diagnosis Code D35.1Benign neoplasm of parathyroid gland

ICD-10-CM Codes›C00–D49›D10-D36›D35

ICD-10-CM D35.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

D35.1 is a billable ICD-10-CM diagnosis code for benign neoplasm of parathyroid gland. 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Benign neoplasms.

Code Identity

ICD-10-CM Code
D35.1
Billable Status
Yes — Valid for Submission
Code Describes
Benign neoplasm of parathyroid gland
Short Description
Benign neoplasm of parathyroid gland
Same as the full description in the CMS dataset.
Parent Code
D35
Benign neoplasm of other and unspecified endocrine glands

Code Classification

ChapterC00–D49Neoplasms
SectionD10-D36Benign neoplasms, except benign neuroendocrine tumors
CategoryD35Benign neoplasm of other and unspecified endocrine glands
This CodeD35.1Benign neoplasm of parathyroid gland

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Benign neoplasm of parathyroid gland
  • Ectopic parathyroid adenoma
  • Parathyroid adenoma

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.

    • Adenoma
      • chief cell
    • Adenoma
      • water-clear cell

Clinical ClassificationClinical

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

CCSR NEO073
Benign neoplasms
Default principal diagnosis: inpatient Yes · outpatient Yes

Table of NeoplasmsClinical

Anatomical sites in the Table of Neoplasms that reference this code family.

SiteMalig.
Primary		Malig.
Secondary		Ca
in situ		BenignUncertainUnspec.
parathyroid (gland)C75.0C79.89D09.3D35.1D44.2D49.7

Patient EducationClinical

Benign Tumors

Tumors are abnormal growths in your body. They can be either benign or malignant. Benign tumors aren't cancer. Malignant ones are. Benign tumors grow only in one place. They cannot spread or invade other parts of your body. Even so, they can be dangerous if they press on vital organs, such as your brain.

Read the full article at MedlinePlus

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

Convert D35.1 to ICD-9-CMHistory

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

ICD-9-CM
227.1 Benign neo parathyroid
Exact Match The mapping is direct, with no qualifiers.

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 D35.1Overview

Is D35.1 (Benign neoplasm of other and unspecified endocrine glands) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report benign neoplasm of parathyroid gland on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does D35.1 group to?

When benign neoplasm of parathyroid gland 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 D35.1?

Under the General Equivalence Mappings, benign neoplasm of parathyroid gland converts to ICD-9-CM 227.1 (benign neo parathyroid). The mapping is a direct match.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.