2021 ICD-10-CM Code N63.21

Unspecified lump in the left breast, upper outer quadrant

  1. ICD-10-CM Index
  2. Chapter: N00–N99
  3. Section: N60-N65
  4. Block: N63
  5. N63.21 - Unspecified lump in the left breast, upper outer quadrant
Version 2021
Replaced Code
Billable Code
Unspecified Code
MS-DRG Mapping

Valid for Submission

N63.21 is a billable diagnosis code used to specify a medical diagnosis of unspecified lump in the left breast, upper outer quadrant. The code N63.21 is valid during the fiscal year 2021 from October 01, 2020 through September 30, 2021 for the submission of HIPAA-covered transactions.

The ICD-10-CM code N63.21 might also be used to specify conditions or terms like lump in upper outer quadrant of left breast.

Unspecified diagnosis codes like N63.21 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

ICD-10:N63.21
Short Description:Unspecified lump in the left breast, upper outer quadrant
Long Description:Unspecified lump in the left breast, upper outer quadrant

Code Classification

Replaced Code

This code was replaced in the 2021 ICD-10 code set with the code(s) listed below. The National Center for Health Statistics (NCHS) has published an update to the ICD-10-CM diagnosis codes which became effective October 1, 2020. This code was replaced for the FY 2021 (October 1, 2020 - September 30, 2021).


  • N63.25 - Unspecified lump in the left breast, overlapping quadrants
  • N63.25 - Unspecified lump in the left breast, overlapping quadrants

Index to Diseases and Injuries

The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10 code(s). The following references for the code N63.21 are found in the index:

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

Replacement Code

N6321 replaces the following previously assigned ICD-10 code(s):

Convert N63.21 to ICD-9 Code

The General Equivalency Mapping (GEM) crosswalk indicates an approximate mapping between the ICD-10 code N63.21 its ICD-9 equivalent. The approximate mapping means there is not an exact match between the ICD-10 code and the ICD-9 code and the mapped code is not a precise representation of the original code.

Information for Patients


Breast Diseases

Most women experience breast changes at some time. Your age, hormone levels, and medicines you take may cause lumps, bumps, and discharges (fluids that are not breast milk).

If you have a breast lump, pain, discharge or skin irritation, see your health care provider. Minor and serious breast problems have similar symptoms. Although many women fear cancer, most breast problems are not cancer.

Some common breast changes are

NIH: National Cancer Institute


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Code History

  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018

Previous Code: N63.20

Related Codes

Next Code: N63.22