11603

Excision, malignant lesion including margins, trunk, arms, or legs; excised diameter 2.1 to 3.0 cm

CPT code 11603 represents the surgical excision of a malignant skin lesion located on the trunk, arms, or legs, where the total excised diameter (the lesion's maximum dimension plus the most narrow margins required for complete removal) is between 2.1 cm and 3.0 cm. This procedure involves a full-thickness removal of the lesion through the dermis and into the subcutaneous fat layer. This specific code is categorized under the integumentary system surgical procedures and is differentiated by the anatomical location and the size of the excision. Clinicians must accurately measure and document the lesion and the planned margin before the excision to determine the correct diameter for coding purposes. The measurement used for reporting is the maximum width of the lesion plus the margins required on either side. For example, if a lesion is 1.6 cm and 0.5 cm margins are taken on each side, the total diameter is 2.6 cm (1.6 + 0.5 + 0.5), which correctly falls into the 11603 range. This procedure is typically performed for biopsy-proven malignancies such as basal cell carcinoma, squamous cell carcinoma, or melanoma in situ. The surgical site is prepared with an antiseptic solution, local anesthesia is administered, and a scalpel is used to excise the tissue in an elliptical or circular fashion. Hemostasis is achieved using cautery or suture ligation. The wound is then closed; simple closure is included in the excision code, while intermediate or complex closures are reported separately. The excised specimen is submitted for histopathological examination to ensure clear margins and confirm the diagnosis.

Clinical Indications

  • Biopsy-proven basal cell carcinoma of the trunk or extremities
  • Biopsy-proven squamous cell carcinoma of the trunk or extremities
  • Malignant melanoma in situ requiring definitive excision
  • Dermatofibrosarcoma protuberans of the trunk or limbs
  • Other histologically confirmed malignant skin neoplasms (e.g., Merkel cell carcinoma)
  • Suspected malignant lesion where the physician determines excision is the most appropriate management

Procedure Steps

  1. Patient identification and surgical site verification (Time Out).
  2. Measurement of the lesion's maximum diameter and marking of the planned surgical margins.
  3. Calculation of the total excised diameter (lesion + margins) to be between 2.1 cm and 3.0 cm.
  4. Application of sterile preparation and draping of the operative site on the trunk, arms, or legs.
  5. Injection of local anesthetic (e.g., lidocaine with epinephrine) to the site.
  6. Full-thickness incision using a scalpel through the dermis and into the subcutaneous fat.
  7. Excision of the specimen, including the marked margins.
  8. Orientation of the specimen using sutures or ink for pathological margin identification.
  9. Attainment of hemostasis using electrocautery or suture ligation.
  10. Performance of simple closure (undermining and suturing) or preparation for separate repair code if indicated.
  11. Application of sterile dressing and post-operative instructions provided to the patient.
  12. Submission of the specimen for histopathological analysis.

Coding Guidelines

  • Code selection is based on the anatomical site (trunk, arms, legs) and the total excised diameter (lesion + margins).
  • The excised diameter must be measured and documented prior to the excision to account for tissue shrinkage.
  • Simple closure is included in the malignant excision code and should not be reported separately.
  • If intermediate (12031-12057) or complex (13100-13153) repair is performed, report it as a separate line item.
  • Report only one excision code per lesion. If multiple lesions are excised, code each separately and append modifier 59 or XS if necessary.
  • For malignant lesions, the pathology should ideally confirm malignancy, though the code is based on the surgeon's clinical judgment at the time of excision.
  • Do not report 11603 in conjunction with Mohs Micrographic Surgery (17311-17315) for the same lesion.
  • Adjacent tissue transfer or rearrangement (14000-14302) performed after excision includes the excision and should be billed instead of 11603.

Associated ICD-10 Codes