Monday 15 July 2013

Correct Coding for Excision of Malignant Skin Lesions



Correct coding of malignant skin lesion excisions can be very complex. Several factors need to be taken into account when choosing the correct codes. These factors include the size of the lesion, the size of the excision, the depth of the excision (skin subcutaneous, fascia, muscle), the location on the body of the lesion and the closure. An understanding of the distinction between the 116XX malignant lesion excision codes and the 2XXXX radical excision malignant codes allows the best prospect for reimbursement if the requirements of each specific code are met and appropriately documented.
Excision malignant lesion codes 11600 to 11646 indicate full thickness excision of a skin lesion including margins. This margin is determined by the diameter of the lesion plus the most narrow margin required to excise the lesion. Since most skin lesions are excised in an elliptical fashion to facilitate an esthetic closure, it is the narrow margin that determines the adequacy of the excision (Example A). These codes are stratified by location in the body and by the dimension of the excision (Table). The malignant lesion excision Current Procedural Terminology (CPT) Codes 11600 to 11646 include simple closure of the wound.

If the diameter of the lesion and the most narrow margin totals more than 4 cm, a 22 modifier should be included and the charge increased appropriately.

When the excision site is closed using an adjacent tissue transfer, whether that involves undermining in order to facilitate the closure, mobilization and placement of a local flap or Z-plasty, the 14000--14350 CPT Codes (adjacent tissue transfer or rearrangement) should be used. These codes include the excision of the defect so that an excision code is not used in addition to the 14XXX Codes.

When the excision site is closed by intermediate or complex closures such as fascia and/or subcutaneous closure, both the excision code and the closure code should be used (Example B).
When the excision extends deep to the subcutaneous tissues involving either fascia or underlying muscle, the radical excision CPT codes in the musculoskeletal section would be appropriate. For example, wide excision of melanoma of the back including subcutaneous tissues and underlying fascia would be coded 21935. If the excision site is covered with a split or full-thickness skin graft, the appropriate graft code should be used in addition to the appropriate excision code (Example C).

Example A
A 1 cm basal cell carcinoma is excised from the arm of a patient. The narrowest margin is 0.5 cm on either side of the lesion. The total narrowest margin measures 2 cm (1 x 0.5 x 0.5). This skin excision deeply extended only down to the subcutaneous tissues. The appropriate code would be 11602. With a simple skin closure, no other code would be appropriate.

Example B
Excision of a basal cell carcinoma from the skin of the neck results in an elliptical excision with a narrowest margin of 2.5 cm. The deep margin of excision included the platysma muscle. A two-layer closure was carried out, including a deep platysma layer and a skin layer. We would recommend an 11623 as the excision code and 12041 as the closure code.

Example C
A 2.5-cm melanoma is excised from the leg. Lateral margins result in a total excision defect of 6 cm with a depth of excision that includes the fascia of the underlying muscle. The defect is closed with a split-thickness skin graft. Correct coding for this procedure would be 27615 (radical excision-malignant lesion, leg or ankle) and 15120 for the split thickness skin graft.

Comment
One of the aggravating aspects of these malignant excision codes is the complexity and difficulty of selecting the correct code or set of codes for any particular situation. In Example B, an excision code and the closure code is one option; if deep margin of excision extends to the underlying muscle fascia, the radical excision codes would be appropriate.

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