2026 ICD-10-CM Diagnosis Code C16.9Malignant neoplasm of stomach, unspecified

ICD-10-CM Codes›C00–D49›C15-C26›C16

ICD-10-CM C16.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

C16.9 is a billable ICD-10-CM diagnosis code for malignant neoplasm of stomach, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 374 through 376. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Gastrointestinal cancers - stomach.

Code Identity

ICD-10-CM Code
C16.9
Billable Status
Yes — Valid for Submission
Code Describes
Malignant neoplasm of stomach, unspecified
Short Description
Malignant neoplasm of stomach, unspecified
Same as the full description in the CMS dataset.
Parent Code
C16
Malignant neoplasm of stomach

Code Classification

ChapterC00–D49Neoplasms
SectionC15-C26Malignant neoplasms of digestive organs
CategoryC16Malignant neoplasm of stomach
This CodeC16.9Malignant neoplasm of stomach, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Adenocarcinoma of stomach
  • Carcinoma of stomach
  • Early gastric cancer
  • Epstein-Barr virus associated gastric carcinoma
  • Gastric adenocarcinoma and proximal polyposis of stomach
  • Gastric polyp
  • Gastric polyposis
  • HER2-positive gastric cancer
  • Hereditary diffuse carcinoma of stomach
  • Late gastric cancer
  • Leiomyosarcoma of stomach
  • Linitis plastica of stomach
  • Local recurrence of malignant neoplasm of stomach
  • Malignant neoplasm of stomach
  • Metastatic gastroesophageal adenocarcinoma
  • Primary carcinoma of stomach
  • Primary carcinoma of stomach due to Epstein-Barr virus disease
  • Primary HER2-positive gastric cancer
  • Primary linitis plastica of stomach
  • Primary malignant mesenchymal neoplasm of stomach
  • Primary malignant neoplasm of stomach
  • Primary squamous cell carcinoma of stomach
  • Primary undifferentiated carcinoma of stomach
  • Squamous cell carcinoma of stomach
  • Undifferentiated carcinoma of stomach

Tabular List NotesGuidance

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

Inclusion Terms

  • Gastric cancer NOS

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.

    • Adenocarcinoma
      • diffuse type
        • unspecified site
    • Adenocarcinoma
      • intestinal type
        • unspecified site
    • Carcinoma(malignant)
      • diffuse type
        • unspecified site
    • Carcinoma(malignant)
      • intestinal type
        • unspecified site
    • Leather bottle stomach
    • Linitis(gastric) plastica

Clinical ClassificationClinical

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

CCSR NEO013
Gastrointestinal cancers - stomach
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Bariatric Surgery

    surgical procedures aimed at affecting metabolism and producing major weight reduction in patients with morbid obesity.

  • Diverticulosis, Stomach

    a pathological condition characterized by the presence of a number of gastric diverticula in the stomach.

  • Diverticulum, Stomach

    saccular, outward protrusion of all or a portion of the wall of the stomach.

  • Gastric Absorption

    uptake of substances via the stomach.

  • Gastric Antral Vascular Ectasia

    a distinct vascular lesion in the pyloric antrum that is characterized by tortuous dilated blood vessels (ectasia) radiating outward from the pylorus. the vessel pattern resembles the stripes on the surface of a watermelon. this lesion causes both acute and chronic gastrointestinal hemorrhage.

  • Gastric Dilatation

    abnormal distention of the stomach due to accumulation of gastric contents that may reach 10 to 15 liters. gastric dilatation may be the result of gastric outlet obstruction; ileus; gastroparesis; or denervation.

  • Gastric Fistula

    abnormal passage communicating with the stomach.

  • Gastric Stump

    that portion of the stomach remaining after gastric surgery, usually gastrectomy or gastroenterostomy for cancer of the stomach or peptic ulcer. it is a common site of cancer referred to as stump cancer or carcinoma of the gastric stump.

  • Gastrointestinal Contents

    the contents included in all or any segment of the gastrointestinal tract.

  • Receptor-Like Protein Tyrosine Phosphatases, Class 3

    a subclass of receptor-like protein tryosine phosphatases that contain a single cytosolic protein tyrosine phosphate domain and multiple extracellular fibronectin iii-like domains.

  • Stomach

    an organ of digestion situated in the left upper quadrant of the abdomen between the termination of the esophagus and the beginning of the duodenum.

  • Stomach Diseases

    pathological processes involving the stomach.

  • Stomach Neoplasms

    tumors or cancer of the stomach.

  • Stomach Rupture

    bursting of the stomach.

  • Stomach Ulcer

    ulceration of the gastric mucosa due to contact with gastric juice. it is often associated with helicobacter pylori infection or consumption of nonsteroidal anti-inflammatory drugs (nsaids).

  • Stomach Volvulus

    twisting of the stomach that may result in gastric ischemia and gastric outlet obstruction. it is often associated with diaphragmatic hernia.

  • Stomach, Avian

    a component of the digestive system of birds which consists of the gizzard and proventriculus.

  • Stomach, Ruminant

    a component of the digestive system of ruminants which consists of the abomasum; omasum; reticulum; and rumen.

Table of NeoplasmsClinical

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

SiteMalig.
Primary		Malig.
Secondary		Ca
in situ		BenignUncertainUnspec.
stomachC16.9C78.89D00.2D13.1D37.1D49.0
stomach › wall NECC16.9C78.89D00.2D13.1D37.1D49.0

Patient EducationClinical

Stomach Cancer

The stomach is an organ between the esophagus and the small intestine. It mixes food with stomach acid and helps digest protein. Stomach cancer mostly affects older people - two-thirds of people who have it are over age 65. Your risk of getting it is also higher if you:

The full article covers:

  • What is Stomach Cancer?

Read the full article at MedlinePlus

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

Convert C16.9 to ICD-9-CMHistory

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

ICD-9-CM
151.9 Malig neopl stomach NOS
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 C16.9Overview

Is C16.9 (Malignant neoplasm of stomach) a billable code?

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

What MS-DRG does C16.9 group to?

When malignant neoplasm of stomach, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 374, 375, 376, with relative weights from 0.9243 to 2.1387 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of C16.9?

Under the General Equivalence Mappings, malignant neoplasm of stomach, unspecified converts to ICD-9-CM 151.9 (malig neopl stomach NOS). The mapping is a direct match.

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.