2026 ICD-10-CM Diagnosis Code D13.99Benign neoplasm of ill-defined sites within the digestive system

ICD-10-CM Codes›C00–D49›D10-D36›D13

ICD-10-CM D13.99
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

D13.99 is a billable ICD-10-CM diagnosis code for benign neoplasm of ill-defined sites within the digestive system. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 393 through 395. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Benign neoplasms.

Code Identity

ICD-10-CM Code
D13.99
Billable Status
Yes — Valid for Submission
Code Describes
Benign neoplasm of ill-defined sites within the digestive system
Short Description
Benign neoplasm of ill-defined sites within the dgstv sys
Parent Code
D13.9
Benign neoplasm of ill-defined sites within the digestive system

Code Classification

ChapterC00–D49Neoplasms
SectionD10-D36Benign neoplasms, except benign neuroendocrine tumors
CategoryD13Benign neoplasm of other and ill-defined parts of digestive system
This CodeD13.99Benign neoplasm of ill-defined sites within the digestive system

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Benign neoplasm of digestive organ
  • Benign neoplasm of gastrointestinal tract
  • Benign neoplasm of intestinal tract
  • Benign neoplasm of Meckel's diverticulum
  • Benign neoplasm of spleen
  • Benign stromal neoplasm of gastrointestinal tract
  • Hamartoma of intestine
  • Hemangioendothelioma
  • Hemangioendothelioma of abdomen
  • Littoral cell angioma
  • Neoplasm of Meckel's diverticulum
  • Neoplasm of uncertain behavior of spleen
  • Red pulp hamartoma
  • Splenic hamartoma

Tabular List NotesGuidance

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

Inclusion Terms

  • Benign neoplasm of digestive system NOS
  • Benign neoplasm of intestine NOS
  • Benign neoplasm of spleen

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

  • Hemangioendothelioma

    a neoplasm derived from blood vessels, characterized by numerous prominent endothelial cells that occur singly, in aggregates, and as the lining of congeries of vascular tubes or channels. hemangioendotheliomas are relatively rare and are of intermediate malignancy (between benign hemangiomas and conventional angiosarcomas). they affect men and women about equally and rarely develop in childhood. (from stedman, 25th ed; holland et al., cancer medicine, 3d ed, p1866)

  • Hemangioendothelioma, Epithelioid

    a tumor of medium-to-large veins, composed of plump-to-spindled endothelial cells that bulge into vascular spaces in a tombstone-like fashion. these tumors are thought to have borderline aggression, where one-third develop local recurrences, but only rarely metastasize. it is unclear whether the epithelioid hemangioendothelioma is truly neoplastic or an exuberant tissue reaction, nor is it clear if this is equivalent to kimura's disease (see angiolymphoid hyperplasia with eosinophilia). (segen, dictionary of modern medicine, 1992)

  • Angiolymphoid Hyperplasia with Eosinophilia

    solitary or multiple benign cutaneous nodules comprised of immature and mature vascular structures intermingled with endothelial cells and a varied infiltrate of eosinophils, histiocytes, lymphocytes, and mast cells.

  • Splenic Hamartoma

    a rare hamartoma that arises from the spleen. the majority of cases are incidental findings in splenectomy specimens or during autopsy.

Table of NeoplasmsClinical

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

SiteMalig.
Primary		Malig.
Secondary		Ca
in situ		BenignUncertainUnspec.
alimentary canal or tract NECC26.9C78.80D01.9D13.99D37.9D49.0
digestive organs, system, tube, or tract NECC26.9C78.89D01.9D13.99D37.9D49.0
gastrocolicC26.9C78.89D01.9D13.99D37.9D49.0
gastrointestinal (tract) NECC26.9C78.89D01.9D13.99D37.9D49.0
intestine, intestinalC26.0C78.80D01.40D13.99D37.8D49.0
intestine, intestinal › tract NECC26.0C78.89D01.40D13.99D37.8D49.0
spleen, splenic NECC26.1C78.89D01.7D13.99D37.8D49.0

Code History & ChangesHistory

Replacement D13.99 replaces the following previously assigned code(s):

  • D13.9 - Benign neoplasm of ill-defined sites within the dgstv sys
FY 2024AddedAdded to the ICD-10-CM code setEffective October 1, 2023.
FY 2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About D13.99Overview

Is D13.99 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report benign neoplasm of ill-defined sites within the digestive system on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does D13.99 group to?

When benign neoplasm of ill-defined sites within the digestive system is the principal diagnosis on an inpatient stay, it groups to MS-DRG 393, 394, 395, with relative weights from 0.6490 to 1.5993 depending on complications. Higher weights mean higher Medicare reimbursement.

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.