2026 ICD-10-CM Diagnosis Code C50.919Malignant neoplasm of unspecified site of unspecified female breast

ICD-10-CM Codes›C00–D49›C50›C50

ICD-10-CM C50.919
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

C50.919 is a billable ICD-10-CM diagnosis code for malignant neoplasm of unspecified site of unspecified female breast. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 582 through 583, 597 through 599. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Breast cancer - all other types.

Code Identity

ICD-10-CM Code
C50.919
Billable Status
Yes — Valid for Submission
Code Describes
Malignant neoplasm of unspecified site of unspecified female breast
Short Description
Malignant neoplasm of unsp site of unspecified female breast
Parent Code
C50.91
Malignant neoplasm of breast of unspecified site, female

Code Classification

ChapterC00–D49Neoplasms
SectionC50Malignant neoplasms of breast
CategoryC50Malignant neoplasm of breast
This CodeC50.919Malignant neoplasm of unspecified site of unspecified female breast

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Adenocarcinoma of breast
  • Blood/lymphatic vessel invasion by tumor absent
  • Blood/lymphatic vessel invasion by tumor indeterminate
  • Blood/lymphatic vessel invasion by tumor present
  • Carcinoma of bone, connective tissue, skin and breast
  • Carcinoma of breast
  • Carcinoma of salivary gland type of breast
  • Eccrine ductal carcinoma
  • Familial cancer of breast
  • Familial ovarian cancer
  • Germline BRCA-mutated, HER2-negative metastatic breast cancer
  • HER2-positive carcinoma of breast
  • Hereditary breast and ovarian cancer syndrome
  • Hidradenocarcinoma
  • Hormone receptor negative neoplasm
  • Hormone receptor positive malignant neoplasm of breast
  • Hormone receptor positive tumor
  • Human epidermal growth factor 2 negative carcinoma of breast
  • Infiltrating duct carcinoma of breast
  • Infiltrating ductal carcinoma of breast, stage 1
  • Infiltrating ductal carcinoma of breast, stage 2
  • Infiltrating ductal carcinoma of breast, stage 3
  • Infiltrating ductal carcinoma of breast, stage 4
  • Infiltrating lobular carcinoma of breast
  • Inflammatory carcinoma of breast
  • Invasive carcinoma of breast
  • Local recurrence of malignant neoplasm of breast
  • Locally advanced breast cancer
  • Malignant melanoma of breast
  • Malignant neoplasm in full remission
  • Malignant neoplasm in partial remission
  • Malignant neoplasm of bone, connective tissue, skin and breast
  • Malignant neoplasm of breast
  • Malignant neoplasm of breast in full remission
  • Malignant neoplasm of breast in partial remission
  • Malignant neoplasm of breast in remission
  • Malignant neoplasm of ectopic site of breast
  • Malignant phyllodes tumor of breast
  • Metaplastic carcinoma of breast
  • Metastatic carcinoma to breast
  • Metastatic human epidermal growth factor 2 positive carcinoma of breast
  • Metastatic lobular carcinoma
  • Mixed ductal and lobular carcinoma of breast
  • Mucinous carcinoma of breast
  • Neoplasm of ectopic site of breast
  • Phyllodes tumor of breast
  • Primary angiosarcoma of breast
  • Primary angiosarcoma of thorax
  • Primary angiosarcoma of trunk
  • Primary carcinoma of breast
  • Primary infiltrating duct carcinoma of breast
  • Primary infiltrating lobular carcinoma of breast
  • Primary inflammatory carcinoma of breast
  • Primary intracystic papillary carcinoma of breast
  • Primary invasive pleomorphic lobular carcinoma of breast
  • Primary malignant neoplasm of breast
  • Primary malignant neoplasm of ectopic site of breast
  • Primary malignant phyllodes tumor of breast
  • Primary metaplastic carcinoma of breast
  • Primary mixed ductal and lobular carcinoma of breast
  • Primary mucinous carcinoma of breast
  • Primary scirrhous carcinoma of breast
  • Primary solid papillary carcinoma with invasion of breast
  • Recurrent primary malignant neoplasm of breast
  • Sarcoma of breast
  • Scirrhous carcinoma of breast
  • Triple-negative breast cancer

Clinical ClassificationClinical

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

CCSR NEO030
Breast cancer - all other types
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Hereditary Breast and Ovarian Cancer Syndrome

    autosomal dominant hereditary cancer syndrome in which a mutation most often in either brca1 or brca2 is associated with a significantly increased risk for breast and ovarian cancers.

  • Neoplastic Syndromes, Hereditary

    the condition of a pattern of malignancies within a family, but not every individual's necessarily having the same neoplasm. characteristically the tumor tends to occur at an earlier than average age, individuals may have more than one primary tumor, the tumors may be multicentric, usually more than 25 percent of the individuals in direct lineal descent from the proband are affected, and the cancer predisposition in these families behaves as an autosomal dominant trait with about 60 percent penetrance.

Patient EducationClinical

Breast Cancer

Breast cancer is a cancer that starts in breast tissue. It happens when cells in the breast change and grow out of control. New cells grow even when you don't need them, and old cells don't die when they should. These extra cells can form a mass called a tumor.

The full article covers:

  • What is breast cancer?
  • What are the types of breast cancer?
  • What causes breast cancer?
  • Who is at risk for breast cancer?
  • What are the signs and symptoms of breast cancer?
  • How is breast cancer diagnosed?
  • What are the treatments for breast cancer?
  • Can breast cancer be prevented?

Read the full article at MedlinePlus

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

Convert C50.919 to ICD-9-CMHistory

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

ICD-9-CM
174.9 Malign neopl breast NOS
Approximate The match is approximate rather than exact.

Code History & ChangesHistory

Replaced This code was replaced in the FY 2026 code set by:

  • C50.A0 - Malignant inflammatory neoplasm of unspecified breast
  • C50.A0 - Malignant inflammatory neoplasm of unspecified breast
  • C50.A0 - Malignant inflammatory neoplasm of unspecified breast
  • C50.A0 - Malignant inflammatory neoplasm of unspecified breast
  • C50.A0 - Malignant inflammatory neoplasm of unspecified breast
  • C50.A0 - Malignant inflammatory neoplasm of unspecified breast
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 C50.919Overview

Is C50.919 (Malignant neoplasm of breast of unspecified site, female) a billable code?

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

What MS-DRG does C50.919 group to?

When malignant neoplasm of unspecified site of unspecified female breast is the principal diagnosis on an inpatient stay, it groups to MS-DRG 582, 583, 597, 598, 599, with relative weights from 0.7332 to 1.9266 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of C50.919?

Under the General Equivalence Mappings, malignant neoplasm of unspecified site of unspecified female breast converts to ICD-9-CM 174.9 (malign neopl breast NOS). 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.