Skip to main content

C57.21 vs Z85.42

C57.21 (Malignant neoplasm of right round ligament) compared with Z85.42 (Personal history of malignant neoplasm of other parts of uterus), 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

Z85.42 is the personal-history or screening code for the active disease C57.21 names, so the two are not interchangeable.

MedCoder-derived
What is different?

The conditions named and chapter.C57.21 is “Malignant neoplasm of right round ligament”; Z85.42 is “Personal history of malignant neoplasm of other parts of uterus”. C57.21 sits in C00-D49 — Neoplasms (C00-D49); Z85.42 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.Z85.42 is the personal-history or screening code for the active disease C57.21 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. Z85.42 is the personal-history or screening code for the active disease C57.21 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.

Official rule

Is there an Excludes2 relationship?

None.Neither entry carries an Excludes2 note that names the other code. Z85.42 carries 2 Excludes2 notes 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

Z85.42
Personal history of malignant neoplasm of other parts of uterus
↔
C57.21
Malignant neoplasm of right round ligament

What we found

History or screening versus active disease.Z85.42 is the personal-history or screening code for the active disease C57.21 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
C57.21

Malignant neoplasm of right round ligament

Z85.42

Personal history of malignant neoplasm of other parts of uterus

StatusSame for both
Billable
Excludes2Differs
C57.21

None at this code

Z85.42
  • personal history of benign neoplasm (Z86.01-)
  • personal history of carcinoma-in-situ (Z86.00-)
Code firstDiffers
C57.21

None at this code

Z85.42
  • any follow-up examination after treatment of malignant neoplasm (Z08)
Use additional codeDiffers
C57.21

None at this code

Z85.42
  • code to identify:
  • alcohol use and dependence (F10.-)
  • exposure to environmental tobacco smoke (Z77.22)
  • history of tobacco dependence (Z87.891)
  • occupational exposure to environmental tobacco smoke (Z57.31)
  • tobacco dependence (F17.-)
  • tobacco use (Z72.0)
Code alsoDiffers
C57.21

None at this code

Z85.42
  • any follow-up examination (Z08-Z09)
CategoryDiffers
C57.21

C57 Malignant neoplasm of other and unspecified female genital organs

Z85.42

Z85 Personal history of malignant neoplasm

ChapterDiffers
C57.21

C00-D49 — Neoplasms (C00-D49)

Z85.42

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

IncludesDiffers
C57.21
  • malignant neoplasm of skin of female genital organs
Z85.42

None at this code

No Excludes1 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