2026 ICD-10-CM Diagnosis Code C50.521Malignant neoplasm of lower-outer quadrant of right male breast

ICD-10-CM Codes›C00–D49›C50›C50

ICD-10-CM C50.521
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

C50.521 is a billable ICD-10-CM diagnosis code for malignant neoplasm of lower-outer quadrant of right male 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. Coders also document this condition as infiltrating duct carcinoma of lower outer quadrant of breast. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Breast cancer - all other types.

Code Identity

ICD-10-CM Code
C50.521
Billable Status
Yes — Valid for Submission
Code Describes
Malignant neoplasm of lower-outer quadrant of right male breast
Short Description
Malig neoplasm of lower-outer quadrant of right male breast
Parent Code
C50.52
Malignant neoplasm of lower-outer quadrant of breast, male

Code Classification

ChapterC00–D49Neoplasms
SectionC50Malignant neoplasms of breast
CategoryC50Malignant neoplasm of breast
This CodeC50.521Malignant neoplasm of lower-outer quadrant of right male breast

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Infiltrating duct carcinoma of lower outer quadrant of breast
  • Infiltrating duct carcinoma of lower outer quadrant of right breast
  • Lump in lower outer quadrant of right breast
  • Primary infiltrating duct carcinoma of lower outer quadrant of breast
  • Primary infiltrating duct carcinoma of lower outer quadrant of right breast
  • Primary malignant neoplasm of lower outer quadrant of breast

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

Patient EducationClinical

Male Breast Cancer

Although breast cancer is much more common in women, men can get it too. It happens most often to men between the ages of 60 and 70.

Read the full article at MedlinePlus

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Convert C50.521 to ICD-9-CMHistory

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

ICD-9-CM
175.9 Mal neo male breast NEC
Approximate The match is approximate rather than exact.

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 C50.521Overview

Is C50.521 (Malignant neoplasm of lower-outer quadrant of breast, male) a billable code?

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

What MS-DRG does C50.521 group to?

When malignant neoplasm of lower-outer quadrant of right male 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 C50.521?

Under the General Equivalence Mappings, malignant neoplasm of lower-outer quadrant of right male breast converts to ICD-9-CM 175.9 (mal neo male breast NEC). 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.