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C50.5 vs Z12.3

C50.5 (Malignant neoplasm of lower-outer quadrant of breast) compared with Z12.3 (Encounter for screening for malignant neoplasm of breast), from the official CMS tabular data. Z12.3 is the personal-history/screening code for the active disease C50.5 names. MedCoder-derived

Relationship

Review

Condition lifecycle relationship

Z12.3
Encounter for screening for malignant neoplasm of breast
↔
C50.5
Malignant neoplasm of lower-outer quadrant of breast

Personal-history or screening code versus the active disease.

Active disease for this site (breast)

A personal-history code describes a condition that no longer exists and is no longer being treated, so it is not interchangeable with the active-disease code for the same site.

Source: CMS Table of Neoplasms (site match derived from the code title)

Can these codes be reported together?

History or screening versus active disease. Z12.3 is the personal-history or screening code for the active disease C50.5 names.

Site match derived from the code’s own title against the CMS/CDC Table of Neoplasms. A personal-history code describes a condition that no longer exists and is no longer being treated, so it is not interchangeable with the active-disease code.

Side by side

C50.5Malignant neoplasm of lower-outer quadrant of breastZ12.3Encounter for screening for malignant neoplasm of breast
Billing statusNon-billable header

Report instead: C50.511, C50.512, C50.519, C50.521, C50.522

Non-billable header

Report instead: Z12.31, Z12.39

ClassificationC00-D49 — NeoplasmsZ00-Z99 — Factors influencing health status and contact with health services
DefinitionMalignant neoplasm of lower-outer quadrant of breast is a non-billable ICD-10-CM category code (C50.5).Encounter for screening for malignant neoplasm of breast is a non-billable ICD-10-CM category code (Z12.3).
Includes
connective tissue of breast
Paget's disease of breast
Paget's disease of nipple
—
Use additional code
code to identify estrogen, and other hormones and factors receptor status (Z17.-)
code to identify any family history of malignant neoplasm (Z80.-)
Edit this comparisonCheck a whole claim

Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources