11640

Excision, Malignant Lesion Including Margins, Face, Ears, Eyelids, Nose, Lips; Excised Diameter 0.5 cm or Less

CPT code 11640 is utilized for the surgical excision of a malignant skin lesion located on anatomically sensitive areas including the face, ears, eyelids, nose, or lips, where the total excised diameter is 0.5 centimeters or less. This procedure involves a full-thickness removal of the malignant growth along with a necessary margin of healthy-appearing tissue to ensure complete oncological clearance. The definition of 'excised diameter' is paramount for correct coding; it is determined by taking the greatest clinical diameter of the lesion and adding the narrowest margin required to adequately excise the malignancy. This measurement must be taken and documented before the incision is made, as the specimen may shrink once removed and placed in fixative. The procedure typically begins with the identification of the lesion's borders under bright light or magnification, followed by the application of local anesthesia, such as lidocaine with epinephrine. The surgeon performs a full-thickness incision through the epidermis and dermis, extending into the subcutaneous fat layer. Hemostasis is meticulously maintained to prevent hematoma formation, especially given the vascularity of the facial region. A simple, single-layer closure of the resulting wound is considered an inherent part of the excision and is not coded separately. However, if the clinical situation necessitates a more intensive reconstruction, such as an intermediate or complex repair, those codes may be reported in addition to 11640. The excised tissue is invariably submitted for histopathological evaluation to confirm the diagnosis of malignancy and to verify that the surgical margins are free of neoplastic cells.

Clinical Indications

  • Biopsy-proven Basal Cell Carcinoma (BCC) of the face, nose, or ears.
  • Biopsy-proven Squamous Cell Carcinoma (SCC) of the lips or eyelids.
  • Malignant Melanoma in situ (Stage 0) requiring narrow-margin excision in facial regions.
  • Other cutaneous malignancies such as Merkel cell carcinoma or sebaceous carcinoma within the defined size limit.
  • Recurrent malignant lesions in the specified anatomical sites where the excised diameter is 0.5 cm or less.

Procedure Steps

  1. Identify and demarcate the malignant lesion and the intended surgical margins using a surgical marker.
  2. Calculate the total excised diameter by adding the widest diameter of the lesion to the narrowest margins on both sides.
  3. Cleanse the surgical site with an antiseptic solution (e.g., chlorhexidine or povidone-iodine) and drape in a sterile fashion.
  4. Administer local anesthetic, typically 1% or 2% lidocaine with 1:100,000 epinephrine.
  5. Perform a full-thickness surgical incision along the marked margins, extending down to the subcutaneous fat.
  6. Undermine the wound edges if necessary to reduce tension, ensuring the excision remains full-thickness.
  7. Excise the specimen and orient it (e.g., with a suture at the 12 o'clock position) for the pathologist.
  8. Achieve hemostasis using electrocautery or chemical cauterization.
  9. Perform a simple, single-layer closure using interrupted or running sutures.
  10. Apply a sterile dressing and provide postoperative wound care instructions to the patient.
  11. Submit the specimen for histopathological analysis.

Coding Guidelines

  • Code selection is based on the anatomical site and the excised diameter (lesion diameter plus the narrowest margins).
  • The measurement must be based on the clinician's documentation of the lesion and margins prior to excision, not the pathologist's measurements of the fixed specimen.
  • Simple (single-layer) closure is included in the 11640 code and should not be reported separately.
  • Intermediate (12041-12057) or complex (13131-13153) repairs may be reported separately if performed and documented.
  • Adjacent tissue transfer or rearrangement (14040-14061) includes the excision of the lesion; if performed, 11640 should not be coded separately.
  • If multiple malignant lesions are excised, report a separate code for each lesion, appending modifier 59 if they are at different sites.
  • For benign lesions of the same size and location, refer to the 11440 series.

Associated ICD-10 Codes