Summary & Overview
CPT 17313: Mohs Micrographic Surgery, First Stage on Trunk/Extremities
Headline: CPT 17313: Mohs micrographic surgery (first stage, trunk/limbs) — scope and payer coverage
Lead: CPT 17313 defines the first-stage Mohs micrographic technique for lesions on the trunk, arms, or legs, including complete tumor removal, mapping, color coding, surgeon-performed microscopic examination, and histologic staining (up to five tissue blocks). This procedure is a cornerstone in skin cancer management when tissue-sparing margin control is essential.
What the code represents and national significance: CPT 17313 codifies the initial stage of Mohs surgery on the trunk and extremities, capturing both the surgical excision and intraoperative pathologic processing performed by the surgeon. Mohs surgery is a nationally recognized technique for high cure rates and tissue conservation in selected skin cancers, making accurate coding important for clinical documentation and payer reimbursement workflows.
Key payers covered: Major national payers include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Coverage and billing expectations commonly address site of service, documented clinical indication, and appropriate linkage to malignant skin neoplasm diagnoses.
Overview of reader takeaways: Readers will find an explanation of the clinical and procedural scope of CPT 17313, typical sites of service, common billing considerations, associated diagnosis codes for skin malignancies, related Mohs procedure codes for additional stages or blocks, and commonly applied modifiers. Data not available in the input will be noted where applicable.
CPT Code Overview
CPT 17313 describes Mohs micrographic technique for the trunk, arms, or legs (first stage, up to 5 tissue blocks). The procedure includes removal of all gross tumor, surgical excision of tissue specimens, mapping and color coding of specimens, microscopic examination of specimens by the surgeon, and histopathologic preparation with routine stains (for example, hematoxylin and eosin or toluidine blue). This is a dermatologic surgical procedure (Mohs micrographic surgery) typically performed in an outpatient facility or office setting (for example, POS 11 or POS 24).
Clinical & Coding Specifications
Clinical Context
A 68-year-old patient presents to a dermatology outpatient clinic with a biopsy-proven cutaneous malignancy on the right forearm. The procedure scheduled is Mohs micrographic surgery on the trunk, arms, or legs to achieve tissue-sparing complete margin control. The clinical workflow: pre-procedure evaluation and informed consent in the office; local anesthesia and excision of the visible tumor; surgeon maps, color-codes, and submits up to five tissue blocks for intraoperative microscopic examination with routine stains (eg, hematoxylin and eosin); if margins are positive, additional stages are performed and reported with appropriate add-on codes; defect reconstruction is completed during the same encounter or scheduled separately. Typical site of service is an outpatient facility or office (POS 11 or POS 24). Payors commonly involved include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, BUCA, and Medicare.
Coding Specifications
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Modifier
59: Distinct procedural service — used when Mohs micrographic surgery is performed on a separate lesion during the same day and must be reported separately from another procedure on the same date of service. -
Associated provider taxonomies:
| Taxonomy Code | Specialty |
|---|---|
207ND0900X | Dermatology |