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D16 vs D21.4

D16 (Benign neoplasm of bone and articular cartilage) compared with D21.4 (Benign neoplasm of connective and other soft tissue of abdomen), 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

These codes should not be reported together because D16’s tabular entry lists D21.4 under Excludes1.

Official rule
What is different?

Title wording and billing status.The titles share “Benign neoplasm of”; D16 says “bone and articular cartilage” where D21.4 says “connective and other soft tissue of abdomen”. D16 is a non-billable header; D21.4 is billable.

Registry fact

Can these codes be reported together?

No.D16’s entry carries an Excludes1 note covering D21.4: “benign neoplasm of synovia (D21.-)”. Both may be reported only when the documentation shows the two conditions are unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes1 relationship?

Yes.D16’s tabular entry: “benign neoplasm of synovia (D21.-)”. The note covers D21.4.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes2 relationship?

None.Neither entry carries an Excludes2 note that names the other code.

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?

One is a header.D16 is a non-billable header, but D21.4 is not one of its subdivisions.

Registry fact

Are there sequencing instructions?

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

Official rule

Are there other coding relationships?

None found.No laterality, encounter-phase, Table of Neoplasms, Table of Drugs and Chemicals, or history-versus-active-disease relationship links these codes.

MedCoder-derived

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?

Excludes1 — generally not reported together

Excludes1 conflict

D16
Benign neoplasm of bone and articular cartilage
↔
D21.4
Benign neoplasm of connective and other soft tissue of abdomen

What we found

No — do not report together.D16 carries an Excludes1 note covering D21.4: “benign neoplasm of synovia (D21.-)”

Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

What to review

Report one of the two. Both may be reported only when the documentation shows the two conditions are unrelated to each other.

Guide: Excludes1 vs Excludes2Check these on a claim

Why it matters

An Excludes1 note means the two conditions are not ordinarily reported together for the same encounter, because the classification treats them as mutually exclusive forms of the same condition. The documented exception is when the two conditions are unrelated to each other.

Source / rule

CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a

Official guidance behind these answers

  • Section I.A.12.a — Excludes1 · applies to: Excludes1

    A type 1 Excludes note is a pure excludes note. It means “NOT CODED HERE!” An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition. An exception to the Excludes1 definition is the circumstance when the two conditions are unrelated to each other. If it is not clear whether the two conditions involving an Excludes1 note are related or not, query the provider. For example, code F45.8, Other somatoform disorders, has an Excludes1 note for "sleep related teeth grinding (G47.63)," because "teeth grinding" is an inclusion term under F45.8. Only one of these two codes should be assigned for teeth grinding. However psychogenic dysmenorrhea is also an inclusion term under F45.8, and a patient could have both this condition and sleep related teeth grinding. In this case, the two conditions are clearly unrelated to each other, and so it would be appropriate to report F45.8 and G47.63 together.

    ICD-10-CM Official Guidelines FY2027

Quoted from the ICD-10-CM Official Guidelines for Coding and Reporting in effect for the release shown. The tabular notes above are the code-level instruction; these sections are the convention that says how such a note is applied. Source document (CMS PDF) · Release and checksum

Side by side

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

Official descriptionDiffers
D16

Benign neoplasm of bone and articular cartilage

D21.4

Benign neoplasm of connective and other soft tissue of abdomen

StatusDiffers
D16
Non-billable header

A header is not reported on a claim; a code beneath it is.

Report instead: D16.00, D16.01, D16.02, D16.10, D16.11

D21.4
Billable
Excludes1Differs
D16
  • benign neoplasm of connective tissue of ear (D21.0)
  • benign neoplasm of connective tissue of eyelid (D21.0)
  • benign neoplasm of connective tissue of larynx (D14.1)
  • benign neoplasm of connective tissue of nose (D14.0)
  • benign neoplasm of synovia (D21.-)
D21.4
  • benign neoplasm of articular cartilage (D16.-)
  • benign neoplasm of cartilage of larynx (D14.1)
  • benign neoplasm of cartilage of nose (D14.0)
  • benign neoplasm of connective tissue of breast (D24.-)
  • benign neoplasm of peripheral nerves and autonomic nervous system (D36.1-)
  • benign neoplasm of peritoneum (D20.1)
  • benign neoplasm of retroperitoneum (D20.0)
  • benign neoplasm of uterine ligament, any (D28.2)
  • benign neoplasm of vascular tissue (D18.-)
  • hemangioma (D18.0-)
  • lipomatous neoplasm (D17.-)
  • lymphangioma (D18.1)
  • uterine leiomyoma (D25.-)
CategoryDiffers
D16

Is itself a category

D21.4

D21 Other benign neoplasms of connective and other soft tissue

ChapterSame for both

C00-D49 — Neoplasms (C00-D49)

IncludesDiffers
D16

None at this code

D21.4
  • benign neoplasm of blood vessel
  • benign neoplasm of bursa
  • benign neoplasm of cartilage
  • benign neoplasm of fascia

No Excludes2, Code first, Use additional code, 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, notes every code shares are dimmed.

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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