21930

Excision of a subcutaneous soft tissue tumor of the back or flank measuring less than 3 cm, with specimen typically submitted for pathologic analysis.

Verified May 8, 2026 · 5 sources ↓

Medicare: $540.76
Work RVU: 4.82
Global, days: 90
Region: Other

Drawn from CMSAAPC

Documentation requirements

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

Source · Editorial brief grounded in 5 cited references ↓

Tumor size documented as the largest diameter plus twice the narrowest margin excised — not just raw lesion dimensions
Anatomic location specified as back or flank, confirming subcutaneous (not intramuscular or deeper) depth
Pathology specimen submission documented — operative note should confirm specimen sent for analysis
Operative note must confirm the approach and that the lesion was fully excised with the margins obtained
If same-day E&M billed with modifier 25, document the separately identifiable medical decision-making beyond routine pre-op assessment

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 25 Significant separate E/M 51 Multiple procedures 52 Reduced services 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 5 cited references ↓

CPT 21930 covers surgical removal of a subcutaneous soft tissue mass — most commonly a lipoma — located in the back or flank region, where the tumor measures less than 3 cm. Size is calculated as the largest lesion diameter plus twice the narrowest margin documented in the operative note. If the surgeon documents a 2.5 cm mass with a 0.5 cm narrowest margin, the codeable size becomes 3.5 cm, which crosses into 21931 territory. Failing to document margins means coding to the raw lesion diameter — leaving reimbursement on the table and potentially undercoding.

The 90-day global period covers all routine post-op care through day 90. If you bill an E&M on the same day as the excision, modifier 25 is required and the visit must reflect a significant, separately identifiable service beyond the standard pre- and post-op work. CMS guidance is explicit: a routine pre-op assessment for a scheduled, elective excision does not qualify for a same-day E&M with modifier 25.

This code sits in the musculoskeletal section (20000 series), not the integumentary section. That distinction matters when the lesion is subcutaneous — use 21930/21931 for soft tissue tumors in the back or flank, not the skin lesion excision codes (11400 series). Billing a skin lesion code for a subcutaneous lipoma is a common mismatch that triggers audits and denials.

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 (4.82) is the surgeon's own effort — the figure physician pay and productivity targets are built on. The total RVU (16.19) adds practice overhead and malpractice, and is what drives the Medicare payment below.

Work RVU	4.82
Practice expense RVU	10.3
Malpractice RVU	1.07
Total RVU	16.19
Medicare national rate	$540.76
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	$540.76
HOPD (APC 5072) Hospital outpatient department	$1,687.37
ASC (PI P3) Ambulatory surgical center (freestanding)	$345.75

Common denial reasons

The recurring reasons claims for CPT 21930 get rejected.

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

Wrong code family: billing 11400-series skin lesion codes for a subcutaneous soft tissue tumor triggers a CPT-to-diagnosis mismatch denial
Size threshold miscalculated: lesion measured without margins, undercoding to 21930 when documented margins push the excision size to 3 cm or greater (21931)
Same-day E&M denied when modifier 25 is absent or when documentation reflects only routine pre-op evaluation for a pre-scheduled elective procedure
Diagnosis code mismatch: ICD-10 code does not support a subcutaneous soft tissue neoplasm of the back or flank region

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 5 cited references ↓

01How do I calculate the size to choose between 21930 and 21931?

Use the largest lesion diameter plus two times the narrowest margin. A 2.5 cm lipoma with a 0.5 cm narrowest margin codes to 21931 (3.5 cm), not 21930. If no margin is documented, you code to the raw diameter — and you're likely leaving money behind.

02Should I use a skin lesion code or 21930 for a lipoma on the back?

Use 21930 for subcutaneous soft tissue tumors (lipomas) in the back or flank. The 11400-series codes apply to skin lesions — a different anatomic layer. Misapplying a skin lesion code to a subcutaneous lipoma creates a CPT-diagnosis mismatch that payers flag on audit.

03Can I bill an E&M on the same day as 21930?

Only if the visit was a significant, separately identifiable service beyond the routine pre-op evaluation. Append modifier 25 to the E&M. CMS is explicit that a standard pre-op assessment for a pre-scheduled elective excision does not qualify. Document distinct medical decision-making to support the claim.

04What is the global period for 21930, and what does it cover?

21930 carries a 90-day global period. That includes the day-before visit, the procedure, and all routine post-op care through day 90. Services unrelated to the excision billed during the global window need modifier 24 (E&M) or modifier 79 (unrelated procedure).

05Is modifier 22 ever appropriate with 21930?

Yes, if the excision was significantly more work than typical — for example, a mass with unusual adherence or location requiring extended operative time. You must document the specific reason in the operative note with time and complexity details. Payers will request records.

06Does 21930 require a pathology report to be billed?

CMS does not make pathology submission a universal condition of payment for 21930, but operative documentation should confirm the specimen was sent for analysis — especially when the diagnosis is a suspected neoplasm. Absence of pathology documentation increases audit risk when the ICD-10 code reflects a neoplasm.

Sources & references

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

Mira Scribe

Mira's AI scribe captures tumor location (back vs. flank), tissue depth (subcutaneous), largest lesion diameter, and the narrowest excision margin from dictation — the combination needed to correctly calculate codeable size and select between 21930 and 21931. It also flags whether a same-day E&M was documented as a separately identifiable service, preventing automatic modifier 25 omission denials.

See how Mira captures CPT 21930 documentation