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CPT 17313: Mohs Micrographic Surgery for Malignant Skin Lesion Excision

CPT code 17313 represents Mohs micrographic surgery, a precision surgical technique used to remove malignant skin lesions by excising tissue in stages with immediate microscopic examination to ensure clear margins. The procedure is clinically important for treating skin cancers where tissue preservation and margin control are critical, including basal cell carcinoma, squamous cell carcinoma, and certain melanomas. Nationwide, Mohs surgery is a key option in dermatologic oncology and reconstructive planning.

This publication examines payer coverage and coding context for CPT code 17313 across major national payers: Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical indications, common billing companions, and related CPT entries for additional stages. The analysis summarizes typical sites of service and service type, and identifies relevant ICD-10 diagnoses commonly associated with Mohs procedures.

The report provides benchmarks and policy-focused summaries useful for billing compliance and revenue cycle staff, including comparisons to adjacent Mohs codes for additional stages or blocks. It also outlines clinical context to aid coding accuracy and claims submission. Data not available in the input are clearly noted where applicable.

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Billing Code Overview

CPT code 17313 describes Mohs micrographic surgery, a staged technique for excising malignant skin lesions layer by layer with immediate histopathologic examination to confirm negative margins. This procedure is a specialized surgical excision method focused on tissue conservation and complete tumor removal.

Service type: Surgical — Mohs micrographic technique

Typical site of service: Outpatient dermatologic surgical setting, often performed in an ambulatory surgery center or dermatology clinic with histopathology capability.

National Reimbursement Benchmarks

Nationally, Medicare's mean rate of $649.20 for CPT 17313 sits below BUCA's average commercial mean of $906.00, creating a gap of $256.80 between public and that commercial benchmark. This gap suggests material variation between Medicare and an aggregated commercial payor average, with BUCA positioned notably higher than Medicare on mean reimbursement for this code.

Dispersion measured as the interquartile range (P75 minus P25) varies across payers: Blue Cross Blue Shield shows a wide spread of $5,948.00 ($1,290.50 - $795.60), UnitedHealth Group has a wide spread of $5,525.00 ($1,087.70 - $535.20), while Aetna's spread is narrower at $3,706.00 ($720.00 - $349.40) and Cigna's is $5,426.00 ($972.60 - $430.00). BUCA's IQR is $5,022.00 ($1,134.60 - $642.40). The tightest IQR is Aetna and the widest is Blue Cross Blue Shield, indicating differences in rate consistency across carriers.

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CPT 17313: Mohs Micrographic Surgery for Malignant Skin Lesion Excision

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Billing Code Overview

Service type: Surgical — Mohs micrographic technique

Typical site of service: Outpatient dermatologic surgical setting, often performed in an ambulatory surgery center or dermatology clinic with histopathology capability.

National Reimbursement Benchmarks

National Payer Mean Reimbursement Rates

Clinical & Coding Specifications

Clinical Context

A 67-year-old patient presents to an outpatient dermatology clinic with a biopsy-proven non-melanoma skin cancer on the right forearm (for example, squamous cell carcinoma or basal cell carcinoma). After review of pathology and staging, the dermatologist–Mohs surgeon schedules 17313 Mohs micrographic surgery to achieve complete margin control. On the day of service the patient is checked in to an ambulatory surgical center; local anesthesia is administered, and sequential excisions and immediate frozen-section histopathologic evaluation are performed until margins are clear. After final margin confirmation, the defect is repaired by the surgeon using primary closure or local flap/graft as clinically appropriate. Typical documentation includes preoperative diagnosis and indication, informed consent, number of Mohs stages and blocks, intraoperative mapping and frozen-section results, reconstruction details, and post-operative instructions.

Coding Specifications

Modifier	Description	When to Use
`59`	Distinct procedural service	When a separate, unrelated procedure is performed on the same day at a different anatomical site from the Mohs surgery.

76 | Repeat procedure by same physician | If the same Mohs procedure is repeated later the same day by the same surgeon.

77 | Repeat procedure by another physician | If another physician repeats the same Mohs procedure on the same day.

52 | Reduced services | When the Mohs procedure is partially reduced or not completed as typically described.

53 | Discontinued procedure | If the Mohs surgery is started but terminated due to extenuating circumstances.

50 | Bilateral procedure | If truly bilateral Mohs procedures are performed on matched anatomic sites and payer requires bilateral reporting (rare for single 17313 which is by site).

26 | Professional component (Note: Not in provided list) | Data not available in the input.

22 | Increased procedural services | When work exceeds typical due to complexity, extensive stages, or difficult reconstruction (use per payer policy).

51 | Multiple procedures | When Mohs is billed with other separate procedures on the same day and payer requires multiple procedure modifier reporting.

59 | Distinct procedural service | (Duplicate entry avoided; already listed above.)

AS | Ambulatory surgical center (facility) | When service is provided in an ambulatory surgical center setting and payer requires this modifier for site-specific reporting.

LT | Left side | When the procedure site is the left-sided extremity and payer requires laterality modifiers.

RT | Right side | When the procedure site is the right-sided extremity and payer requires laterality modifiers.

Taxonomy Code	Specialty	Notes
`207ND0900X`	Dermatology	Providers performing clinical evaluation and surgical management of skin cancers.

207NS0135X | MOHS-Micrographic Surgery | Specialty taxonomy for fellowship-trained Mohs surgeons performing micrographic surgery.

207N00000X | Dermatopathology | Pathology services for frozen-section interpretation during Mohs procedures.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`C43.61`	Malignant melanoma of right upper limb, including shoulder	Melanoma is a malignant skin tumor; Mohs is less commonly used for invasive melanoma but may be considered in select situations or for margins of certain melanoma in situ variants.

C43.62 | Malignant melanoma of left upper limb, including shoulder | See above; documents laterality for surgical planning and billing.

C43.71 | Malignant melanoma of right lower limb, including hip | Melanoma diagnosis affecting lower extremity; laterality important for procedure coding and site-specific documentation.

C43.72 | Malignant melanoma of left lower limb, including hip | See above for left-sided lesions.

C44.602 | Unspecified malignant neoplasm of skin of right upper limb, including shoulder | Non-specific malignant skin neoplasm coding for right upper extremity lesions when specific histology is not captured in claim-level coding.

C44.609 | Unspecified malignant neoplasm of skin of left upper limb, including shoulder | Left-sided counterpart; supports medical necessity for Mohs surgery.

C44.612 | Basal cell carcinoma of skin of right upper limb, including shoulder | Common indication for Mohs surgery to ensure complete excision with tissue-sparing technique on cosmetically or functionally sensitive sites.

C44.619 | Basal cell carcinoma of skin of left upper limb, including shoulder | Left-sided basal cell carcinoma; supports Mohs as preferred technique.

C44.622 | Squamous cell carcinoma of skin of right upper limb, including shoulder | Squamous cell carcinoma is an indication for Mohs when high-risk features or location warrant tissue-conserving margin control.

C44.629 | Squamous cell carcinoma of skin of left upper limb, including shoulder | Left-sided SCC; used for laterality and medical necessity documentation.

C44.702 | Unspecified malignant neoplasm of skin of right lower limb, including hip | Supports Mohs for right lower extremity malignant skin lesions when histology is unspecified.

C44.709 | Unspecified malignant neoplasm of skin of left lower limb, including hip | Left lower extremity unspecified malignant skin neoplasm.

C44.729 | Squamous cell carcinoma of skin of left lower limb, including hip | SCC of left lower limb; Mohs may be indicated for tumor control and margin assessment.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`17314`	Mohs micrographic technique, including removal of all gross tumor, surgical excision of tissue specimen, preparation and microscopic examination of specimens, and reporting; each additional stage on trunk, arms, or legs	Billed when additional Mohs stages beyond the initial stage(s) are required on the trunk, arms, or legs during the same operative session.

17315 | Mohs micrographic surgery; additional blocks after the first 5 blocks | Used when more than five tissue blocks are submitted during the Mohs procedure and additional block charges are required.

CPT 17311: Mohs Micrographic Surgery, First Stage (Sensitive Sites)

CPT-17312-MOHS-MICROGRAPHIC-SURGERY-FOR-SKIN-MALIGNANCY

CPT 17312: Mohs Micrographic Surgery for Cutaneous Malignancy

CPT-17314-MOHS-MICROGRAPHIC-SURGERY-SKIN-LESION

CPT 17314: Mohs Micrographic Surgery for Malignant Skin Lesion

CPT-17315-MOHS-MICROGRAPHIC-SURGERY-SKIN-CANCER-EXCISION

CPT 17315: Mohs Micrographic Surgery for Malignant Skin Lesions

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Jul 29, 2026.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.

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Clinical & Coding Specifications

Clinical Context

Coding Specifications

Modifier	Description	When to Use
`59`	Distinct procedural service	When a separate, unrelated procedure is performed on the same day at a different anatomical site from the Mohs surgery.