Coding Skin Cancers in ICD-10: Public Awareness Raises Questions

July’s designation as UV Safety Month comes as no surprise. July is the month of summer vacations, beach trips, and plenty of other outdoor activities. Because I have a family history of skin cancer, UV Safety Month holds a unique and important personal importance. When I was asked to author an article for the July issue of ICD-10monitor, skin cancer coding struck me as the perfect topic.

Did You Know?

Skin cancer rates are on the rise. In fact, skin cancer has become the most frequently diagnosed form of cancer in the U.S., according to the American Cancer Society. The Skin Cancer Foundation notes that every year there are “more new cases of skin cancer than the combined incidence of cancers of the breast, prostate, lung and colon.”

Several factors are contributing to the rise in skin cancer diagnoses nationwide:

• Skin is the largest organ in the human body.
• The UV index is changing due to a diminished ozone layer – and even low-index days present a risk.
• Patient awareness lags behind other, more publicized cancers.

While basal cell and squamous cell carcinomas are the most common forms of skin cancer, melanomas are the most deadly, with an estimated 10,000 Americans dying from melanoma in 2017. According to the Skin Cancer Foundation, an estimated 87,110 new cases of invasive melanoma will be diagnosed in the U.S. in 2017. Melanoma can be caused by too much exposure to ultraviolet (UV) rays from the sun or other sources, such as tanning beds and sun lamps.

Successful prevention measures include being aware of the UV index, early detection, and reducing UV exposure. During UV Safety Month, it is important to note the following UV index levels and associated protection recommendations:

Breaking Down the Diagnosis: Cell Type Matters

Clinical coding of skin cancers is based on two key factors: the type of cell involved and anatomical site. As mentioned above, basal and squamous cell are the most common types. These types of skin cancers are usually treated topically in the physician’s office and require minimal coding expertise. However, melanoma is more invasive, and treatment typically includes a hospital encounter with radical wide excision, skin grafts, and lymph node excision.

Coding Melanomas: Definitions and Staging

In ICD-10-CM, melanoma is differentiated as melanoma or melanoma in situ. Melanoma is reported with codes from category C43, while melanoma in situ is reported with codes in category D03. To better understand the ICD-10-CM classification of these two conditions, the coder first must understand the definitions of these terms and how melanomas are staged.

Melanoma in situ has invaded the epidermis layer only, and is described as Stage 0. However, malignant melanoma is a malignant neoplasm that has invaded the dermis and is described as Stage I through IV, depending on several factors:

• The thickness of the neoplasm
• Whether the neoplasm is ulcerated
• If the neoplasm has spread or metastasized

Stage I

Stage IA: The melanoma is less than 1.0 mm in thickness. It is not ulcerated and has not been found in lymph nodes or distant organs.

Stage IB: The melanoma is less than 1.0 mm in thickness and is ulcerated, OR it is between 1.01 and 2.0 mm and is not ulcerated. It has not been found in lymph nodes or distant organs.

Stage II

Stage IIA: The melanoma is between 1.01 mm and 2.0 mm in thickness and is ulcerated, OR it is between 2.01 and 4.0 mm and is not ulcerated. It has not been found in lymph nodes or distant organs.

Stage IIB: The melanoma is between 2.01 mm and 4.0 mm in thickness and is ulcerated, OR it is thicker than 4.0 mm and is not ulcerated. It has not been found in lymph nodes or distant organs.

Stage IIC: The melanoma is thicker than 4.0 mm and is ulcerated. It has not been found in lymph nodes or distant organs.

Stage III

Stage IIIA: The melanoma can be of any thickness, but it is not ulcerated. It has spread to one to three lymph nodes near the affected skin area, but the nodes are not enlarged and the melanoma is found only when they are viewed under the microscope. There is no distant spread.

Stage IIIB: One of the following applies:

• The melanoma can be of any thickness and is ulcerated. It has spread to one to three lymph nodes near the affected skin area, but the nodes are not enlarged and the melanoma is found only when they are viewed under the microscope. There is no distant spread.
• The melanoma can be of any thickness, but it is not ulcerated. It has spread to one to three lymph nodes near the affected skin area. The nodes are enlarged because of the melanoma. There is no distant spread.
• The melanoma can be of any thickness, but it is not ulcerated. It has spread to small areas of nearby skin (satellite tumors) or lymphatic channels (in-transit tumors) around the original tumor, but the nodes do not contain melanoma. There is no distant spread.

Stage IIIC: One of the following applies:

• The melanoma can be of any thickness and is ulcerated. It has spread to one to three lymph nodes near the affected skin area. The nodes are enlarged because of the melanoma. There is no distant spread.
• The melanoma can be of any thickness and is ulcerated. It has spread to small areas of nearby skin (satellite tumors) or lymphatic channels (in-transit tumors) around the original tumor, but the nodes do not contain melanoma. There is no distant spread.
• The melanoma can be of any thickness and may or may not be ulcerated. It has spread to four or more nearby lymph nodes, OR to nearby lymph nodes that are clumped together, OR it has spread to nearby skin (satellite tumors) or lymphatic channels (in-transit tumors) around the original tumor and to nearby lymph nodes. The nodes are enlarged because of the melanoma. There is no distant spread.

Stage IV

The melanoma has spread beyond the original area of skin and nearby lymph nodes to other organs such as the lung, liver, brain, or distant areas of the skin, subcutaneous tissue, or distant lymph nodes. Neither spread to nearby lymph nodes, and thickness is not considered in this stage, but typically the melanoma is thick and has also spread to the lymph nodes. For example, former President Carter’s melanoma was classified as Stage IV since it metastasized to his brain and liver.

In ICD-10-CM, documentation is required specifying whether the melanoma is in situ (which is captured with ICD-10-CM code D03, Melanoma in situ) or if the melanoma has invaded the dermis (which is captured with ICD-10-CM code C43, Malignant melanoma of skin). Fourth and fifth digits are assigned for the specific body site.

Don’t Forget the Body Site

In ICD-10-CM, body sites are much more specific than in ICD-9-CM and require documentation of laterality for paired organs such as eyes, ears, and upper and lower limbs. They include:

• Lip
• Eyelid
  • Right
  • Left
  • Unspecified
• Ear/external auricular canal
  • Right
  • Left
  • Unspecified
• Nose
• Other specified parts of face
• Unspecified parts of face
• Scalp/neck
• Anal skin
• Breast
• Other parts of trunk
• Upper limb, including shoulder
  • Right
  • Left
  • Unspecified
• Lower limb, including hip
  • Right
  • Left
  • Unspecified
• Overlapping sites
• Unspecified sites

Coders must pay close attention to the body site when coding melanomas and seek to capture the most specific anatomical position possible. Especially during UV Awareness Month, the above information about coding melanomas is important for every coder to know and share.