Resection of a soft tissue tumor on the back or flank where the tumor diameter plus required margins measures less than 5 cm.
Verified May 8, 2026 · 5 sources ↓
- Medicare
- $955.93
- Work RVU
- 15.33
- Global, days
- 90
- Region
- Other
Documentation requirements
What must appear in the operative or office note to support the claim.
Source · Editorial brief grounded in 5 cited references ↓
- Pathology or imaging confirming malignant soft tissue tumor (e.g., sarcoma) at the back or flank location
- Operative note specifying tumor size and margin measurements totaling less than 5 cm
- Documentation of wide resection technique including extent of tissue removed beyond gross tumor margins
- Anatomical location of the tumor within the back or flank clearly stated — not just 'soft tissue mass'
- Final or intraoperative pathology report confirming diagnosis and margin status
- If modifier 22 is appended, explicit documentation of factors making the case substantially more complex than typical
Applicable modifiers
Modifiers commonly billed with this code.
Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual
What this code covers
Source · Editorial summary grounded in 5 cited references ↓
CPT 21935 covers wide excision of a soft tissue malignant tumor — most commonly sarcoma — located on the back or flank, where the combined tumor-plus-margin measurement is under 5 cm. The resection is not limited to the visible tumor boundary; it extends into surrounding tissue and anatomical structures considered at risk for involvement. That wide-margin intent distinguishes this from simple excision codes and drives the documentation standard.
This code carries a 90-day global period. All routine post-op visits, wound checks, and dressing changes through day 90 are bundled. If an unrelated procedure is performed in that window by the same surgeon, append modifier 79. An unplanned return to the OR for a related complication uses modifier 78.
When complex wound closure is required — for example, layered repair or flap reconstruction — a separate repair code such as 13101 may be reportable. NCCI bundles some repair codes with 21935; check the current PTP edit table and append modifier 59 or XS if the repair is clinically distinct and documentation supports it.
RVU & reimbursement
Component RVUs and Medicare national rate. Actual payment varies by GPCI locality.
Source · CMS Physician Fee Schedule, RVU26A · January 2026
Work RVU vs. total RVU
The work RVU (15.33) is the surgeon's own effort — the figure physician pay and productivity targets are built on. The total RVU (28.62) adds practice overhead and malpractice, and is what drives the Medicare payment below.
| Work RVU | 15.33 |
| Practice expense RVU | 9.68 |
| Malpractice RVU | 3.61 |
| Total RVU | 28.62 |
| Medicare national rate | $955.93 |
| Global period | 90 days |
Payment by site of service
Medicare pays different rates by setting. HOPD typically pays substantially more than ASC for the same procedure.
Source · CMS OPPS Addendum B·ASC HCPCS payment rates·2026
| Setting | Medicare rate (national) |
|---|---|
Office (PFS non-facility) Procedure performed in physician's office | $955.93 |
HOPD (APC 5073) Hospital outpatient department | $2,967.63 |
ASC (PI G2) Ambulatory surgical center (freestanding) | $1,248.36 |
Common denial reasons
The recurring reasons claims for CPT 21935 get rejected.
Source · Editorial brief grounded in CMS NCCI edits, AAOS coding appeals, and cited references ↓
- Tumor size not documented — payer cannot confirm the less-than-5-cm threshold was met
- Operative note describes limited excision rather than wide resection with margins, triggering downcoding
- Bundling denial when complex repair code (e.g., 13101) is billed same-day without a modifier to indicate distinct service
- ICD-10 diagnosis does not support malignancy — benign soft tissue tumor diagnoses may prompt downcoding to 21930
- Missing pathology report in the record at time of audit, leading to medical necessity denial
Frequently asked questions
Source · Generated from the editorial pipeline, verified against 5 cited references ↓
01What separates 21935 from 21930?
02Can I bill complex wound closure separately with 21935?
03What ICD-10 codes are typically paired with 21935?
04How does the 90-day global period affect billing for post-op complications?
05When is modifier 22 appropriate for 21935?
06Is an assistant surgeon reimbursable for 21935?
Sources & references
Editorial content was developed using the following public sources. Last verified May 8, 2026.
- 01CMS Physician Fee Schedule 2026
- 02mdclarity.comhttps://www.mdclarity.com/cpt-code/21935
- 03aapc.comhttps://www.aapc.com/codes/cpt-codes/21935
- 04cms.govhttps://www.cms.gov/medicare/coding-billing/ncci-medicare
- 05cms.govhttps://www.cms.gov/files/document/02-chapter2-ncci-medicare-policy-manual-2025finalcleanpdf.pdf
Mira Scribe
Mira's AI scribe captures the tumor location (back vs. flank), resection technique (wide excision with margins), and the combined tumor-plus-margin measurement directly from dictation. It also flags whether complex wound closure was performed in the same session. This prevents the most common audit failure for 21935: an operative note that documents tumor removal without explicitly stating margin dimensions or confirming wide-resection intent — the two facts that justify this code over a simple excision.
See how Mira captures CPT 21935 documentation