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January 13, 2021

Medical Coding for Common Dermatological Conditions

Written by: Amy Wagner, MEd, CPC, CHA, ICDCT-CM

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Coding for dermatology can be tricky.  Since many procedures can be considered cosmetic if not properly coded to show the medical necessity, billers and coders must pay careful attention to the documentation to avoid unnecessary denials or time-consuming appeals. Let’s take a look at some common conditions, and review what is covered and what isn’t.  Remember, medical necessity is determined by what your provider documents.  It may be necessary to educate your providers to carefully document all symptoms that are relevant to the medical necessity of the procedures. Furthermore, if the medical necessity is not there, providers must know when an ABN is warranted before performing a procedure that may not be covered, and billers should brush up on the proper modifiers that may be relevant when an ABN is presented to the patient.   


Actinic Keratoses

Actinic Keratoses (AK) is an extremely common dermatological condition among the elderly.  It is considered to be a pre-malignant condition; therefore, procedures to destroy or remove actinic keratoses are generally covered by Medicare and commercial payers. The condition presents as rough, sometimes red, scaly patches on the skin, usually where there has been the greatest exposure to damaging UV rays such as the face, scalp, neck, ears, forearms, and hands. While they are technically benign lesions, the majority of squamous cell carcinomas begin as actinic keratoses, making it preferable to remove or destroy them before they progress to malignancy. 

ICD-10-CM
L57.0                    Actinic keratoses
Category L57 includes a “Use additional code” note to identify the source of the ultraviolet radiation (W89), if known.

CPT Coding

Typical treatment for Actinic Keratoses is destruction, usually cryotherapy. Cryotherapy involves applying liquid nitrogen to the lesion to destroy it.  The lesion will blister and peel off over a short period of time, usually a few days to a few weeks.  The following destruction codes include laser surgery, electrosurgery, cryosurgery, chemosurgery, and surgical curettement).

  17000                  Destruction, premalignant lesion, First Lesion
+17003                  Destruction, premalignant lesion, second through 14 lesions, each
                              (list separately in addition to code for first lesion)
  17004                  Destruction, premalignant lesions, 15 or more lesions

Seborrheic Keratoses

Unlike Actinic Keratoses, Seborrheic Keratoses are benign lesions.  For this reason, their removal is often considered to be cosmetic.  It is important for billers and coders working in dermatology to be very familiar with payer policies.  There are instances in which it is medically necessary to remove these benign lesions and the documentation must be very specific as to the accompanying symptoms. 

The ICD-10-CM code to use for a seborrheic keratoses is:

L82.0                                   Inflamed seborrheic keratoses
L82.1                                     Other seborrheic keratoses


If the lesion is subject to recurrent trauma, such as rubbing from contact with clothing, or If one or more of the following conditions is present and clearly documented in the medical record, Medicare may consider the removal of a seborrheic keratoses to be medically necessary:

R58                                       Bleeding
R20.8                                    Pain
L29.9                                     Intense itching


A statement of "irritated skin lesion" will be insufficient justification for lesion removal when used solely to describe a complaint or the physician's physical findings. Similarly, use of an ICD-10 code L82.0 (Inflamed seborrheic keratosis) will be insufficient to justify lesion removal, without the medical record documentation of the patients' symptoms and physical findings. It is important to document the patient's signs and symptoms as well as the physician’s physical findings. 


Check the NCD / LCD for other instances that may warrant medically necessary removal of benign lesions. If the beneficiary wishes one or more of these benign asymptomatic lesions removed for cosmetic purposes, the beneficiary becomes liable for the service rendered. The physician has the responsibility to notify the patient in advance that Medicare will not cover cosmetic dermatological surgery and that the beneficiary will be liable for the cost of the service. It is strongly advised that the beneficiary, by his or her signature, accept responsibility for payment. Charges should be clearly stated and an ABN should be signed and retained in the patient’s file with the appropriate modifiers used if the patient wishes for the claim to be filed. 


Malignant Lesions

Basal cell carcinoma, squamous cell carcinoma, and melanoma are common, treatable forms of skin cancer.  A dermatologist who suspects malignancy will take a biopsy by excising the lesion and sending it for pathological testing.  Confirmation of malignancy may warrant Mohs micrographic surgery.  Let’s look at coding for these common dermatological procedures.

ICD-10-CM

Malignant melanomas can be found in category C43.  Basal cell and squamous cell carcinomas are both coded in category C44. 

Category C43 Malignant Melanoma of Skin

4th and 5th characters are used to designate location and laterality, for example: 

  • C43.7               Malignant melanoma of lower limb, including hip
  • C43.70             Malignant melanoma of unspecified lower limb, including hip
  • C43.71             Malignant melanoma of right lower limb, including hip
  • C43.72             Malignant melanoma of left lower limb, including hip

Category C44 Other and unspecified malignant neoplasm of skin

Additional characters are used to designate type of carcinoma, location, and laterality, for example:

  • C44.11               Basal cell carcinoma of skin of eyelid, including canthus
  • C44.111             Basal cell carcinoma of skin of unspecified eyelid, including canthus
  • C44.112             Basal cell carcinoma of skin of right eyelid, including canthus
  • C44.119             Basal cell carcinoma of skin of left eyelid, including canthus
  • C44.4                Other and unspecified malignant neoplasm of skin of scalp and neck
  • C44.40               Unspecified malignant neoplasm of skin of scalp and neck
  • C44.41               Basal cell carcinoma of skin of scalp and neck
  • C44.42               Squamous cell carcinoma of skin of scalp and neck
  • C44.49               Other specified malignant neoplasm of skin of scalp and neck
CPT Coding

Know the difference between biopsy and removal.  A biopsy is a sample of a suspicious lesion on the body. The tissue is sent to a laboratory for testing. 

11100                Biopsy of skin, subcutaneous tissue and/or mucous membrane (including simple closure), unless otherwise listed, single lesion
+11101              each separate / additional lesion (List separately in addition to code for primary procedure).


Shave excisions are removals of lesions without taking the full thickness of the skin. These codes include local anesthesia. The wounds do not require suture closure. Choose your specific CPT code based on the lesion location and size.

11300-11313       Shaving of epidermal or dermal lesions


Excision codes are dependent on whether the lesion is benign or malignant. Excision is defined as full-thickness removal of a lesion, including margins, and includes simple (nonlayered) closure when performed. CPT code choice is based on the lesion location and size. 

11400-11446       Excision – Benign Lesions
11600-11646       Excision – Malignant Lesions


MOHS SURGERY

A coder must know the difference between stages and blocks.  In Mohs surgery, the surgeon removes layers of tissue.  Each layer is a stage of the surgery.  The layers of tissue are divided into blocks, which are mapped.  The surgeon checks the pieces of the tumor for cancerous cells.  If malignancy is found in any of the blocks, the surgeon goes back and removes another layer of tissue, divides it into one or more blocks, and repeats the process.  Stages continue until no cancerous cells are found in any of the tissue blocks. 


17311      Mohs micrographic technique, including removal of all gross tumor, surgical excision of tissue specimens, mapping, color coding of specimens, microscopic examination of specimens by the surgeon, and histopathologic preparation including routine stain(s), head, neck, hands, feet, genitalia, or any location with surgery directly involving muscle, cartilage, bone, tendon, major nerves, or vessels; first stage, up to 5 tissue blocks


+17312     each additional stage after the first stage, up to 5 tissue blocks (list separately in addition to code for primary procedure)

(Use 17312 in conjunction with 17311)


17313       Mohs micrographic technique, including removal of all gross tumor, surgical excision of tissue specimens, mapping, color coding of specimens, microscopic examination of specimens by the surgeon, and histopathologic preparation including routine stain(s), of the trunk, arms, of legs; first stage, up to 5 tissue blocks


+17314      each additional stage after the first stage, up to 5 tissue blocks (list separately in addition to code for primary procedure)

(Use 17314 in conjunction with 17313)


+17315      Mohs micrographic technique, including removal of all gross tumor, surgical excision of tissue specimens, mapping, color coding of specimens, microscopic examination of specimens by the surgeon, and histopathologic preparation including routine stain(s), each additional block after the first 5 tissue blocks, any stage (list separately in addition to code for primary procedure)

(Use 17315 in conjunction with 17311-17314)


Once the lesions are completely removed, a code of Z85.820, Personal history of malignant melanoma of skin or Z85.828, Personal history of other malignant neoplasm of skin is used. The patient is considered to be at higher risk for recurrence of malignant lesions and an annual full-skin exam is recommended. 



Resources
  • LCD ID L34200
  • LCD ID A57044
  • LCD ID L33818

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