2026 ICD-10-CM Diagnosis Code D15.0Benign neoplasm of thymus

ICD-10-CM Codes›C00–D49›D10-D36›D15

ICD-10-CM D15.0
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

D15.0 is a billable ICD-10-CM diagnosis code for benign neoplasm of thymus. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 814 through 816. Coders also document this condition as benign neoplasm of superior mediastinum. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Benign neoplasms.

Code Identity

ICD-10-CM Code
D15.0
Billable Status
Yes — Valid for Submission
Code Describes
Benign neoplasm of thymus
Short Description
Benign neoplasm of thymus
Same as the full description in the CMS dataset.
Parent Code
D15
Benign neoplasm of other and unspecified intrathoracic organs

Code Classification

ChapterC00–D49Neoplasms
SectionD10-D36Benign neoplasms, except benign neuroendocrine tumors
CategoryD15Benign neoplasm of other and unspecified intrathoracic organs
This CodeD15.0Benign neoplasm of thymus

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Benign neoplasm of superior mediastinum
  • Benign neoplasm of thymus
  • Benign thymoma
  • Myasthenia gravis associated with thymoma
  • Thymoma

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Type 1 Excludes

  • benign carcinoid tumor of the thymus D3A.091

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.

    • Thymoma
      • microscopic

Clinical ClassificationClinical

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

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

Clinical InformationClinical

  • Thymoma

    a neoplasm originating from thymic tissue, usually benign, and frequently encapsulated. although it is occasionally invasive, metastases are extremely rare. it consists of any type of thymic epithelial cell as well as lymphocytes that are usually abundant. malignant lymphomas that involve the thymus, e.g., lymphosarcoma, hodgkin's disease (previously termed granulomatous thymoma), should not be regarded as thymoma. (from stedman, 25th ed)

  • Benign Thymoma

    a thymoma that is completely surrounded by a capsule, without evidence of capsular invasion, infiltration of the surrounding tissues, and metastases.

  • Experimental Organism Benign Thymoma Neoplasm|THYMOMA, BENIGN

    a benign neoplasm of the thymus, originating from epithelial thymus cells.

Table of NeoplasmsClinical

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

SiteMalig.
Primary		Malig.
Secondary		Ca
in situ		BenignUncertainUnspec.
thymus (gland)C37C79.89D09.3D15.0D38.4D49.89

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 D15.0 to ICD-9-CMHistory

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

ICD-9-CM
212.6 Benign neoplasm thymus
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 D15.0Overview

Is D15.0 a billable code?

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

What MS-DRG does D15.0 group to?

When benign neoplasm of thymus is the principal diagnosis on an inpatient stay, it groups to MS-DRG 814, 815, 816, with relative weights from 0.6320 to 2.1267 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of D15.0?

Under the General Equivalence Mappings, benign neoplasm of thymus converts to ICD-9-CM 212.6 (benign neoplasm thymus). 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.