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C50.922 vs Z12.31

C50.922 (Malignant neoplasm of unspecified site of left male breast) compared with Z12.31 (Encounter for screening mammogram for malignant neoplasm of breast), from the official CMS tabular data.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 28, 2026 · All releases and sources

Summary

Z12.31 is the personal-history or screening code for the active disease C50.922 names, so the two are not interchangeable.

MedCoder-derived
What is different?

The conditions named and chapter.C50.922 is “Malignant neoplasm of unspecified site of left male breast”; Z12.31 is “Encounter for screening mammogram for malignant neoplasm of breast”. C50.922 sits in C00-D49 — Neoplasms (C00-D49); Z12.31 in Z00-Z99 — Factors Influencing Health Status and Contact with Health Services (Z00-Z99).

Registry fact

Can these codes be reported together?

Not for the same condition.Z12.31 is the personal-history or screening code for the active disease C50.922 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.

MedCoder-derivedGuide: History codes (Z codes)

Are there other coding relationships?

Yes.History or screening versus active disease. Z12.31 is the personal-history or screening code for the active disease C50.922 names.

MedCoder-derivedGuide: History codes (Z codes)

Nothing found in 4 other checks; 1 check does not apply
Is there an Excludes1 relationship?

None.Neither entry carries an Excludes1 note that names the other code. C50.922 carries 1 Excludes1 note and Z12.31 carries 2 Excludes1 notes covering other codes; the side-by-side table quotes them.

Official rule

Is there an Excludes2 relationship?

None.Neither entry carries an Excludes2 note that names the other code. Z12.31 carries 1 Excludes2 note covering other codes; the side-by-side table quotes them.

Official rule

Is one more specific?

Not comparable.The codes sit in different categories; specificity is only comparable within one category.

Is one a parent or header code?

No.Both are billable codes, and neither contains the other.

Registry fact

Are there sequencing instructions?

None.Neither entry carries a Code First or Use Additional Code note that names the other.

Official rule

Official rule: a tabular instructional note or a section of the ICD-10-CM Official Guidelines, quoted as published. Registry fact: the codes’ own published attributes (titles, billable status, position in the hierarchy, code set). MedCoder-derived: a reading MedCoder computes from those facts; it is not itself a rule. How to read the labels

Can these codes be reported together?

Review

Condition lifecycle relationship

Z12.31
Encounter for screening mammogram for malignant neoplasm of breast
↔
C50.922
Malignant neoplasm of unspecified site of left male breast

What we found

History or screening versus active disease.Z12.31 is the personal-history or screening code for the active disease C50.922 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.

What to review

Report the history code when the condition no longer exists and is no longer treated; report the active-disease code while it is.

Guide: History codes (Z codes)Check these on a claim

Why it matters

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 / rule

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

Side by side

Similar descriptions do not make codes interchangeable. The documentation and the official instructions decide which code applies.

Official descriptionDiffers
C50.922

Malignant neoplasm of unspecified site of left male breast

Z12.31

Encounter for screening mammogram for malignant neoplasm of breast

StatusSame for both
Billable
Excludes1Differs
C50.922
  • skin of breast (C44.501, C44.511, C44.521, C44.591)
Z12.31
  • inconclusive mammogram (R92.2)
  • encounter for diagnostic examination-code to sign or symptom
Excludes2Differs
C50.922

None at this code

Z12.31
  • examinations related to pregnancy and reproduction (Z30-Z36, Z39.-)
Use additional codeDiffers
C50.922
  • code to identify estrogen, and other hormones and factors receptor status (Z17.-)
Z12.31
  • code to identify any family history of malignant neoplasm (Z80.-)
CategoryDiffers
C50.922

C50 Malignant neoplasm of breast

Z12.31

Z12 Encounter for screening for malignant neoplasms

ChapterDiffers
C50.922

C00-D49 — Neoplasms (C00-D49)

Z12.31

Z00-Z99 — Factors Influencing Health Status and Contact with Health Services (Z00-Z99)

IncludesDiffers
C50.922
  • connective tissue of breast
  • Paget's disease of breast
  • Paget's disease of nipple
Z12.31

None at this code

No Code first, Code also and 7th character note at either code.

Notes are the code’s own tabular entry, quoted as published. A note that names the other code is the one the verdict above rests on. In a row that differs, each code’s own notes are listed under it, and the notes every code shares are listed once beneath them.

Edit this comparisonCheck a whole claim

Derived from the official CMS ICD-10-CM tabular data (FY2027). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources