CPT® Code 11406

Quick Reference

• Code definition: CPT 11406 covers full-thickness excision of a benign cutaneous or subcutaneous lesion (excluding skin tags) from the trunk, arms, or legs, where the total excised specimen diameter exceeds 4.0 cm.
• Key billing rule: Code selection is driven by the excised specimen diameter (lesion plus margins, measured at time of excision), not the pre-excision clinical lesion size and not the wound length. The MUE is 2 units per date of service.
• Modifier essentials: Modifier 59 (or XU/XE/XP/XS) when reporting alongside another procedure that could otherwise be bundled; modifier 51 for secondary procedures at the same session; modifier 25 (not 57) when an E&M is billed on the same date given the 10-day global period.
• Documentation must-have: The operative report must state the measured excised specimen diameter in centimeters, including margins. Documentation of only the pre-excision lesion size is insufficient to support this code.
• Top confusion point: Simple closure (12001–12007) is bundled into 11406 and is never separately reportable. Only intermediate (12031–12037) or complex (13100–13102) closure may be added separately.
• Payer alert: Medicare covers benign lesion excision only when medically necessary. Cosmetic excisions without documented clinical indication (pain, growth, infection risk, functional interference) will deny. An ABN is required before performing non-covered cosmetic excisions for Medicare beneficiaries.
• Global period: 10-day minor global ("010"). Modifier 57 (decision for surgery) does NOT apply to this code; use modifier 24 for unrelated E&M services during the global period.

When to Use This Code

CPT 11406 applies when a surgeon performs a full-thickness excision of a benign lesion from the trunk, arms, or legs, and the excised specimen diameter exceeds 4.0 cm. The code captures the entire surgical episode: local anesthesia, incision through the dermis circumscribing the lesion with margins, removal of the specimen, hemostasis, and simple (single-layer) wound closure.

Clinical scenarios: Large lipomas causing discomfort or functional interference, epidermoid (sebaceous) cysts with a history of infection or rupture, dermatofibromas with rapid growth, pyogenic granulomas, and benign melanocytic nevi with clinical concern are the most common indications. The specimen is routinely submitted for histologic evaluation, which is separately reportable (typically billed by pathology as 88305).

Anatomic boundaries define the series:

• Trunk = chest wall, abdomen, back, flanks, proximal shoulders
• Arms = upper extremities distal to shoulder, excluding hands and fingers
• Legs = lower extremities distal to hip, excluding feet and toes

Lesions on the neck, hands, feet, or genitalia fall under the 11420–11426 series. Lesions on the face, ears, eyelids, nose, or lips fall under 11440–11446. Using 11406 for neck or hand lesions is a wrong-series error.

Skin tags are excluded. Skin tag removal, regardless of size or body site, is reported with 11200–11201. Coding a skin tag as 11406 is a compliance error.

Benign vs. malignant at time of service: Code selection is based on the clinical/operative diagnosis at the time of service. If pre-operative assessment is benign and the excised specimen exceeds 4.0 cm, 11406 is correct. If post-operative pathology returns a malignant diagnosis, the claim must be corrected to 11606.

Settings: This procedure is performed in office, outpatient clinic, or ASC settings. It appears on the ASC-covered surgical list (ASC payment based on OPPS relative payment weight). Hospital outpatient (Part B) is covered through a comprehensive APC.

Code Differentiation Table

The critical differentiator between 11406 and 11404 is a single centimeter: an excised specimen of exactly 4.0 cm uses 11404; a specimen of 4.1 cm uses 11406. When the operative report is ambiguous, query the surgeon before coding.

The musculoskeletal subcutaneous tumor codes (21930–21936, 27043, 27337, etc.) apply when the context is a soft-tissue tumor resection reported under the musculoskeletal system guidelines. CPT guidelines direct coders to use 11400–11406 for benign cutaneous-origin lesions (e.g., sebaceous cysts) even when those lesions are on musculoskeletal sites such as the back or thigh.

flowchart TD
    A[Benign lesion excision\ntrunk, arm, or leg?] -->|No — neck/hand/foot| B[Use 11420–11426 series]
    A -->|Yes| C{Excised specimen\ndiameter cm}
    C -->|≤0.5| D[11400]
    C -->|0.6–1.0| E[11401]
    C -->|1.1–2.0| F[11402]
    C -->|2.1–3.0| G[11403]
    C -->|3.1–4.0| H[11404]
    C -->|>4.0| I[11406]
    I --> J{Pathology\nconfirms?}
    J -->|Benign| K[Keep 11406]
    J -->|Malignant| L[Correct to 11606]

Billing & Modifier Rules

Modifier 59 / XU / XS / XE / XP: When 11406 is billed alongside another surgical procedure at the same session that could be interpreted as overlapping, append modifier 59 (or the appropriate X modifier as required by the MAC) to the secondary code to establish the distinct procedural service. When billing two lesion excisions at the same session, append modifier 59 to the lower-valued code.

Modifier 51: CMS applies standard multiple-procedure payment reduction rules to 11406 (multiple procedure indicator = 2). When 11406 is one of several surgical procedures at the same session, the secondary procedures are subject to the 50% payment reduction. Bill the highest-value procedure first; append modifier 51 to subsequent procedures as applicable.

Modifier 22: When operative complexity substantially exceeds typical (e.g., extensive adhesions from prior surgery, difficult deep dissection around named structures), modifier 22 is appropriate. CMS requires documentation and typically a cover letter; expect routine denial and appeal.

Modifier 25 vs. 57: 11406 carries a 10-day minor global. Modifier 25 applies if a separate, significant E&M service is provided on the day of the procedure. Modifier 57 (decision for surgery) applies only to procedures with a 90-day major global and is incorrect for 11406.

Modifier 24: For E&M services furnished during the 10-day post-operative global period for an unrelated condition, append modifier 24 to the E&M.

Modifiers that do NOT apply: Bilateral modifier 50 (bilateral indicator = 0 per CMS); co-surgeon modifier 62 (not permitted); team surgery modifier 66 (not permitted).

Closure coding:

MUE = 2: A maximum of 2 units of 11406 per beneficiary per date of service. Billing three or more units requires separate line items with modifier 59/XU on additional units, supporting documentation for each distinct excision, and may require individual consideration review.

Global package (010): The 10-day global includes the pre-operative visit on the day of surgery, intraoperative services, and routine uncomplicated post-operative care for 10 days. It does not include treatment of complications requiring a return to the operating room (modifier 78) or services for unrelated conditions (modifier 79 for procedures, modifier 24 for E&M).

Documentation Essentials

The operative report must contain:

1. Anatomic site with laterality: Specific region (e.g., "left mid-back," "right upper arm") confirming trunk, arm, or leg anatomy, which determines the correct series.
2. Measured excised specimen diameter: The greatest single dimension of the specimen including margins, stated in centimeters at the time of excision. A statement of lesion size alone (e.g., "3 cm lesion") without specimen measurement does not support 11406.
3. Method of removal: Full-thickness excision through the dermis. This distinguishes excision from shave removal (11300 series) or destruction (17000 series).
4. Closure type: Simple, intermediate, or complex. This drives whether additional closure codes are reportable. If closure type is not documented, auditors may deny the separately-billed closure code.
5. Pre-operative diagnosis and medical necessity: Clinical indication for removal (symptoms, growth pattern, diagnostic concern). For Medicare, cosmetic indication alone fails medical necessity review.
6. Pathology submission: Documentation that the specimen was sent to pathology supports the coding of 88305 by the laboratory and validates the benign vs. malignant diagnosis code.

Audit red flags specific to 11406:

• Operative note states only the pre-excision lesion size without a post-excision specimen measurement. Auditors routinely downcode to a smaller-diameter code when the documented size would not reach the 4.0 cm threshold.
• Billing simple closure (12001) alongside 11406. This is a per-procedure NCCI bundling violation; auditors will recoup the closure payment.
• A benign ICD-10-CM diagnosis code on the claim when the pathology report in the medical record shows a malignant diagnosis. This discordance is a False Claims Act risk.
• Multiple units of 11406 without distinct operative documentation for each separately excised lesion at its own measured diameter.

Medicare, Commercial & Medicaid Payer Rules

Medicare:

CMS covers excision of benign skin lesions when the medical record establishes a clinical indication beyond cosmetic appearance. Accepted indications include: lesion causing pain, bleeding, or infection; rapid or change in growth pattern raising malignancy concern; lesion interfering with function or normal activities; or recurrence following prior excision. Cosmetic excision without clinical indication is non-covered; providers must issue an Advance Beneficiary Notice (ABN) prior to performing the service if coverage is uncertain.

Multiple MACs have Local Coverage Determinations (LCDs) for skin lesion removal that specify acceptable ICD-10-CM diagnosis codes. Coders should verify the applicable LCD for their MAC jurisdiction via the CMS Medicare Coverage Database. LCD policies vary by jurisdiction; a diagnosis acceptable under one MAC may not meet criteria under another.

The ASC payment indicator for 11406 is active (covered under the ASC surgical list, payment based on OPPS relative payment weight). The APC status indicator is "hospital Part B services paid through a comprehensive APC."

Commercial payers:

Commercial payers generally follow AMA CPT guidelines for excision coding but may apply prior authorization requirements for lesions above a certain size threshold or for specific diagnoses. Some payers have automated edits that deny intermediate closure when reported with excision unless the medical record documents the layered closure technique. Submit operative reports proactively for large excisions when payer policy is unclear.

Common Denials and Prevention

Insufficient documentation of excised size The claim lists 11406 but the operative note documents only the clinical lesion measurement, not the excised specimen diameter. Without a specimen measurement exceeding 4.0 cm, the code cannot be validated. Prevention: Establish a documentation template or surgeon reminder that requires recording specimen measurement in centimeters at time of excision. If a query is needed post-operatively, use a compliant physician query process before coding.

Bundling of simple closure 12001 is billed alongside 11406 on the same claim. CMS NCCI edits bundle simple closure into the excision code; the claim will deny or recoup the closure payment. Prevention: Never code 12001–12007 with excision codes. Only report closure codes 12031 and above, and only when layered or complex technique is documented.

Cosmetic denial (Medicare medical necessity) Claim denied as cosmetic/not medically necessary. This occurs when the clinical documentation does not establish a symptom-based or diagnostic indication. Prevention: Confirm the operative note and any associated E&M note contain explicit documentation of symptoms or clinical change. If the indication is solely cosmetic, issue an ABN before the procedure, collect patient acknowledgment, and bill the patient directly.

Wrong anatomic series 11406 is used for a lesion on the hand, neck, or foot. These sites require the 11420–11426 series; using 11406 is a miscoded claim that may pay initially but can be recouped on audit. Prevention: Map the documented anatomic site to the correct code series before submission. Trunk/arms/legs = 11400–11406; all other sites require a different series.

Benign/malignant mismatch 11406 is submitted with a benign diagnosis code but pathology returns malignant. The claim, if paid, represents a miscoded service. Prevention: Implement a workflow to reconcile pathology results with submitted claims. When pathology confirms malignancy after the initial claim is paid, file a corrected claim to 11606 with the appropriate malignant ICD-10-CM code.

Coding Scenarios

Scenario 1: Large lipoma, mid-back, simple closure

A 52-year-old Medicare patient presents with a 3 cm lipoma on the mid-back, growing over 18 months and causing positional discomfort. The surgeon excises the lesion with 1 cm margins circumferentially; the excised specimen measures 5.0 cm. The wound is closed with a single-layer suture.

Correct coding: 11406 + D17.1

Why: Specimen size (5.0 cm) exceeds the 4.0 cm threshold; anatomic site is trunk; diagnosis is lipoma. Simple closure is bundled; do not add 12001. Pathology submits 88305 separately.

Scenario 2: Epidermal cyst, upper arm, intermediate closure required

A 45-year-old patient has a 3.8 cm epidermal cyst on the posterior upper arm with a history of rupture. The surgeon excises with margins; total specimen = 4.3 cm. The defect requires a two-layer (dermis and skin) closure for adequate wound approximation.

Correct coding: 11406 + 12032-51 + L72.0

Why: Excised diameter >4.0 cm with upper arm anatomy meets 11406. Intermediate closure (layered) is separately reportable; modifier 51 applies to the secondary procedure. Do not use 12001 (bundled).

Scenario 3: Two benign nevi excised same session, abdomen and thigh

At the same session, a dermatologist excises two benign nevi: an abdominal lesion (excised diameter 4.5 cm) and a right thigh lesion (excised diameter 2.3 cm).

Correct coding: 11406 + 11403-51-59 + D22.5 (abdomen) + D22.70 (thigh)

Why: Each excision is coded independently based on its own specimen diameter and location. Sizes are not combined. Modifier 59 on 11403 establishes the distinct service; modifier 51 applies the multiple-procedure reduction. Pathology submits 88305 x2 separately.

Scenario 4: Post-operative pathology confirms malignancy

A surgeon excises a 4.2 cm lesion from the abdomen with a clinical diagnosis of benign dermatofibroma. Claim is submitted as 11406 with D23.5. Pathology report two weeks later returns: squamous cell carcinoma in situ.

Correct action: File a corrected claim replacing 11406 with 11606 and replacing D23.5 with D04.5 (carcinoma in situ, skin of trunk).

Why: When pathology confirms malignancy, the appropriate code is the malignant excision code for the same site and size. Knowingly retaining an incorrect benign code after receiving the pathology report creates False Claims Act liability.

Related Codes

• 11400 — Benign excision, trunk/arms/legs; ≤0.5 cm — smallest tier in this series
• 11402 — Benign excision, trunk/arms/legs; 1.1–2.0 cm — mid-range tier
• 11404 — Benign excision, trunk/arms/legs; 3.1–4.0 cm — next lower tier, one centimeter below 11406 threshold
• 11606 — Malignant excision, trunk/arms/legs; >4.0 cm — parallel code when pathology returns malignant
• 11426 — Benign excision, scalp/neck/hands/feet/genitalia; >4.0 cm — same size threshold, different anatomic series
• 12032 — Intermediate repair, trunk/extremities, 2.6–7.5 cm — separately reportable layered closure commonly added to 11406
• 13100 — Complex repair, trunk; 1.1–2.5 cm — separately reportable complex closure
• 88305 — Surgical pathology, Level IV — separately reported by pathology for histologic evaluation of the excised specimen

Sources

1. AMA CPT Professional Edition — Integumentary System guidelines, Surgery/Integumentary/Removal of Skin Lesions (11400–11406 series) — Official code descriptors, parenthetical instructions, and size measurement guidelines
2. CMS NCCI Policy Manual for Medicare Services, Chapter 5 (Skin, Subcutaneous Tissue) — Bundling edits, MUE values, and unbundling rules for excision codes
3. CMS Medicare Claims Processing Manual, Publication 100-04, Chapter 12 (Physicians/NPPs) — Global surgical package rules, documentation requirements, modifier application
4. CMS Medicare Coverage Database — MAC-specific LCDs for skin lesion removal — Jurisdiction-specific ICD-10-CM diagnosis code requirements for medical necessity coverage
5. HHS OIG Work Plan — Dermatology billing and skin lesion upcoding — Compliance risk areas for excision coding including specimen size inflation and unbundling of closure codes