21933

Surgical removal of a subfascial (e.g., intramuscular) soft tissue tumor from the back or flank measuring 5 cm or greater in greatest diameter plus required margin.

Verified May 8, 2026 · 6 sources ↓

Medicare: $700.08
Work RVU: 10.85
Global, days: 90
Region: Other

Drawn from CMSAAPCFacsMdclarityFindacode

Documentation requirements

What must appear in the operative or office note to support the claim.

Source · Editorial brief grounded in 6 cited references ↓

Record the greatest diameter of the tumor plus the narrowest margin required for complete excision, measured at time of excision — not from imaging.
Specify the anatomic location as back or flank and confirm the tumor is subfascial (e.g., intramuscular), not subcutaneous.
Document tissue depth explicitly; subfascial vs. subcutaneous distinction drives code selection and will be audited.
If complex closure is billed separately, document why primary approximation was not possible and describe the repair technique used.
Include pathology report or intraoperative findings confirming tumor type (benign vs. malignant) to support medical necessity and defend against cutaneous-origin downcoding.
Note any unusual anatomic or clinical complexity if modifier 22 is appended — quantify additional time or describe the specific challenge.

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 51 Multiple procedures 58 Staged or related 59 Distinct service 78 Unplanned return — related 79 Unrelated during global LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 6 cited references ↓

CPT 21933 covers excision of a deep soft tissue tumor of the back or flank — below the fascia, including intramuscular locations — where the tumor plus the margin required for complete excision measures at least 5 cm. Size is determined at the time of excision by measuring the greatest diameter of the tumor plus the narrowest adequate margin, not the pre-operative imaging estimate. This is the key documentation gatekeeping point: if the measurement is not explicitly recorded in the operative note, payers will downcode or deny.

Code selection within the back/flank tumor family turns on two variables: depth (subcutaneous vs. subfascial) and size (less than 5 cm vs. 5 cm or greater). 21933 is the largest, deepest tier. Cutaneous-origin lesions — sebaceous cysts, melanoma requiring soft-tissue excision — are not reportable here; those go to the integumentary system codes (11400–11446 or 11600–11646).

Complex wound closure after tumor excision is a recurring billing dispute. Simple and intermediate repair are bundled into 21933. Complex repair (13100 series) may be separately reportable when direct approximation was not possible, but this requires explicit documentation of why primary closure was inadequate — not just the repair codes appended with modifier 59. The 90-day global period means all routine post-op care through day 90 is included; unrelated procedures in that window need modifier 79, and staged or related returns need modifier 78 or 58 respectively.

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 (10.85) is the surgeon's own effort — the figure physician pay and productivity targets are built on. The total RVU (20.96) adds practice overhead and malpractice, and is what drives the Medicare payment below.

Work RVU	10.85
Practice expense RVU	7.47
Malpractice RVU	2.64
Total RVU	20.96
Medicare national rate	$700.08
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	$700.08
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 21933 get rejected.

Source · Editorial brief grounded in CMS NCCI edits, AAOS coding appeals, and cited references ↓

Tumor size not documented at time of excision — payer downcodes to the sub-5 cm code 21932 when operative note lacks an explicit measurement.
Lesion coded as cutaneous origin (sebaceous cyst, melanoma) billed under 21933 instead of integumentary system codes 11400–11646.
Complex repair codes (13100 series) denied as bundled when documentation doesn't explain why direct approximation failed.
Modifier 59 appended to complex repair without adequate documentation of a distinct procedural circumstance, triggering NCCI edit denial.
Global period violation — post-op services billed without modifier 24 or 79 within the 90-day global window.

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 6 cited references ↓

01How is the 5 cm threshold measured for 21933?

Measure the greatest diameter of the tumor plus the narrowest margin required for complete excision at the time of surgery. Pre-operative imaging measurements do not control code selection — the intraoperative measurement does, and it must appear in the operative note.

02Can complex repair codes be billed with 21933?

Simple and intermediate repair are bundled and not separately reportable. Complex repair (13100 series) can be billed separately when direct approximation was not possible, but the operative note must document why — not just list the repair codes. Appending modifier 59 without that narrative will not overcome the NCCI edit.

03What is the global period for 21933 and what does it include?

21933 carries a 90-day global period. The day-before pre-op visit, the surgery itself, and all routine post-op care through day 90 are included. Bill unrelated procedures in that window with modifier 79; staged or related returns use modifier 58 (planned) or 78 (unplanned).

04Is 21933 appropriate for a sebaceous cyst or melanoma on the back?

No. Cutaneous-origin lesions — including sebaceous cysts and melanoma requiring soft-tissue excision — belong to integumentary system codes (11400–11446 for benign, 11600–11646 for malignant). Using 21933 for those will draw a denial or audit.

05When does modifier 22 apply to 21933?

Modifier 22 applies when the work is substantially greater than typical — unusual tumor depth, adherence to adjacent neurovascular structures, or markedly increased operative time. The operative note must quantify or describe the specific added complexity; a bare modifier 22 without narrative support will be rejected.

06What distinguishes 21933 from 21932?

Both cover subfascial back/flank tumor excision. 21932 is for tumors measuring less than 5 cm (tumor plus margin). 21933 is for 5 cm or greater. The size measurement in the operative note is the sole differentiator and the first thing auditors check.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

Mira Scribe

Mira's AI scribe captures the tumor's measured greatest diameter plus excision margin from dictation at the time of surgery, confirms the subfascial depth descriptor, and flags the anatomic site as back or flank. It also flags when a complex closure is dictated, prompting the surgeon to document why primary approximation was not achievable — the single most common reason complex repair add-on claims are denied alongside 21933.

See how Mira captures CPT 21933 documentation