Code seborrheic keratosis from category L82.-: L82.0 for inflamed seborrheic keratosis and L82.1 for other seborrheic keratosis (including seborrheic keratosis NOS). Code malignant melanoma of the skin from category C43.-, using C43.9 only when the documentation does not identify a more specific site. Do not confuse seborrheic keratosis with seborrheic dermatitis (L21.-), which is a separate inflammatory condition. Because the two growths can look alike, the code always follows the provider’s documented diagnosis (benign vs. malignant) and, for melanoma, the anatomical site.
What Is Seborrheic Keratosis?
Seborrheic keratosis is a common, harmless, benign skin growth similar to a mole. These growths usually start appearing in a person’s 30s or 40s and may multiply with age. Dermatology sources such as the American Academy of Dermatology also describe them as common, non-contagious growths.
Seborrheic keratoses are sometimes called epidermal tumors because they are clusters of extra cells in the epidermis, the outermost layer of skin. That term does not mean they are cancerous. Certain moles and warts are also classified as epidermal tumors.
- Common locations: trunk, face, and under the breasts, though they can develop almost anywhere on the skin.
- Number of lesions: some people have only a few, while others have several dozen.
- Why coders care: the growths can resemble melanoma, so correct diagnosis documentation matters for code assignment.
What Does Seborrheic Keratosis Look Like?
- A round or oval patch with a distinctive stuck-on appearance
- Uniform look with well-defined borders, often waxy or scaly
- Usually raised, and texture can often be felt even when it looks flat
- Usually brown, but can also be black or tan
- Caused by a buildup of keratin, the same fibrous protein found in fingernails, hooves, and horns
- Some contain small cyst-like structures that look like bubbles; others look scabby or wart-like
- Often appear in numbers and change slowly, gradually growing and developing their texture
What Causes Seborrheic Keratosis?
The exact cause is unknown, but several factors may contribute:
- Sun exposure may increase occurrence, according to some studies.
- Genetics may play a role, since they appear more often in families.
- They are not caused by viral or bacterial infections.
They are generally harmless, but some people have itching, irritation from friction, or bleeding if a growth is scratched or injured. If many growths erupt suddenly, or existing lesions change noticeably, seek medical advice from a provider.
What Is Melanoma, and How Does It Differ?
Melanoma is a skin cancer that starts in melanocytes, the cells that produce melanin, the pigment that gives skin its color. It usually develops on sun-exposed skin such as the arms, back, face, and legs. It can also form in the eyes and, rarely, inside the body, such as in the nose or throat. Clinical references such as the Merck Manual melanoma overview list the major risk factors and warning signs in more detail.
Melanoma Risk Factors
- UV exposure from sunlight, tanning lamps, and tanning beds
- A history of severe sunburns
- Fair skin, light-colored eyes or hair
- Personal or family history of melanoma
- Certain inherited genetic mutations
- A weakened immune system
- The number and type of moles a person has
Melanoma can develop from an existing mole, but most melanomas begin as new growths, so changes in existing moles and new lesions both deserve attention.
What Does Melanoma Look Like?
Melanoma varies widely. Suspicious features include an asymmetrical shape, ragged or poorly defined borders, multiple colors, and changes in size, shape, or color over time. Not every melanoma shows all of these features.
Table 1: Seborrheic Keratosis vs. Melanoma at a Glance
| Feature | Seborrheic keratosis | Melanoma |
|---|---|---|
| Nature | Benign (harmless) epidermal growth | Malignant skin cancer of the melanocytes |
| Typical look | Round or oval, stuck-on, waxy or scaly, well-defined borders | Often asymmetrical, ragged borders, multiple colors, may change over time |
| Usual color | Brown, black, or tan | Varies; may contain several colors |
| Common sites | Trunk, face, under the breasts | Sun-exposed skin such as arms, back, face, and legs |
| Cause | Unknown; sun exposure and genetics may contribute | UV exposure is a major risk factor |
| ICD-10-CM category | L82.- | C43.- |
ICD-10-CM Coding for Seborrheic Keratosis (L82.-)
Accurate coding depends on separating benign seborrheic keratosis from malignant melanoma and on the specific characteristics the provider documents. When a lesion is removed or sampled, the procedure coding follows the provider’s note, so see our guides on skin procedure and biopsy coding and biopsy vs. excision coding for the CPT side.
Table 2: ICD-10-CM Category L82.- (Seborrheic Keratosis)
| Code | Description |
|---|---|
| L82.0 | Inflamed seborrheic keratosis |
| L82.1 | Other seborrheic keratosis (includes seborrheic keratosis NOS) |
Category L82.- also includes basal cell papilloma, dermatosis papulosa nigra, and Leser-Trélat disease.
Don’t Confuse Seborrheic Keratosis With Seborrheic Dermatitis (L21.-)
Seborrheic dermatitis is a separate inflammatory skin condition classified under category L21.-. Code selection depends on the specific type the provider documents.
Table 3: ICD-10-CM Category L21.- (Seborrheic Dermatitis)
| Code | Description |
|---|---|
| L21.0 | Seborrhea capitis |
| L21.1 | Seborrheic infantile dermatitis |
| L21.8 | Other seborrheic dermatitis |
| L21.9 | Seborrheic dermatitis, unspecified |
Use L21.8 when the documentation names a type of seborrheic dermatitis that no more specific code describes. Use L21.9 when the type is not specified.
ICD-10-CM Coding for Melanoma (C43.-)
Malignant melanoma of the skin is classified under category C43.-. Use C43.9 (malignant melanoma of skin, unspecified) when the documentation does not identify a more specific skin location. When the site is documented, choose the matching C43 code. The same principle of site-specific coding applies across skin conditions, as shown in our third-degree burn ICD-10-CM coding guide.
Table 4: ICD-10-CM Category C43.- (Malignant Melanoma of Skin) by Site
| Code | Site |
|---|---|
| C43.0 | Lip |
| C43.1- | Eyelid, including canthus (inner and outer corners of the eye) |
| C43.2- | Ear and external auricular canal (any part of the external ear and ear canal visible from the outside) |
| C43.31 | Nose |
| C43.39 | Other parts of the face |
| C43.4 | Scalp and neck |
| C43.5- | Trunk, including skin of the breast and anal skin |
| C43.6- | Upper limbs, including shoulder |
| C43.7- | Lower limbs, including hip |
| C43.8 | Overlapping sites (at least two contiguous sites when the point of origin cannot be determined) |
| C43.9 | Malignant melanoma of skin, unspecified |
Codes ending in a dash require additional characters, such as laterality, so confirm the full code in the current code set. Code sets change each fiscal year, so check the latest FY 2027 ICD-10-CM code updates before finalizing codes.
Documentation Tips for Coders and CDI Teams
Since seborrheic keratosis and melanoma can look similar, the code must rest on the provider’s documented diagnosis, not on how a lesion is described. A clear record supports accurate coding and helps your team follow an operative note coding checklist.
- Is the diagnosis stated as benign (seborrheic keratosis) or malignant (melanoma)?
- For seborrheic keratosis, is it inflamed (L82.0) or other/NOS (L82.1)?
- For melanoma, is the specific site documented (for example, scalp and neck vs. trunk)?
- If the lesion spans adjacent sites with an unknown point of origin, is it documented as overlapping (C43.8)?
- Is the condition seborrheic keratosis or seborrheic dermatitis? Check that the provider did not mean the L21.- category.
- If the diagnosis is uncertain until pathology returns, wait for the final provider-documented diagnosis before assigning the final code.
Frequently Asked Questions (FAQ)
What is the ICD-10-CM code for seborrheic keratosis?
Seborrheic keratosis is classified under L82.-. Use L82.0 for inflamed seborrheic keratosis and L82.1 for other seborrheic keratosis, including seborrheic keratosis NOS.
Is seborrheic keratosis cancerous?
No. It is a common, benign skin growth. It is sometimes called an epidermal tumor because it consists of extra cells in the epidermis, but that does not mean it is cancer.
What is the difference between seborrheic keratosis and seborrheic dermatitis?
Seborrheic keratosis is a benign skin growth (L82.-). Seborrheic dermatitis is an inflammatory skin condition (L21.-). They are coded from different categories.
What is the ICD-10-CM code for malignant melanoma of the skin?
Malignant melanoma of the skin is classified under category C43.-. C43.9 is used when the documentation does not identify a more specific site.
Which melanoma code is used for the scalp and neck?
C43.4 reports malignant melanoma of the scalp and neck.
What does C43.8 mean?
C43.8 is for overlapping sites, meaning the melanoma covers at least two adjacent sites and the point of origin cannot be determined.
Can seborrheic keratosis look like melanoma?
Yes. The growths can resemble melanoma, which is why accurate provider documentation of the diagnosis is essential for correct code assignment.
Key Takeaways
- L82.0 and L82.1 report seborrheic keratosis; C43.- reports malignant melanoma of the skin.
- Seborrheic keratosis (L82.-) is not seborrheic dermatitis (L21.-).
- Use C43.9 only when no more specific melanoma site is documented.
- Site-specific C43 codes cover the lip, eyelid, ear, nose, face, scalp and neck, trunk, limbs, and overlapping sites.
- The provider’s documented diagnosis decides the code, because benign and malignant lesions can look alike.
References
- American Academy of Dermatology: Seborrheic Keratoses Overview. Patient-facing description of seborrheic keratosis, its appearance, and why it can look like skin cancer.
- Merck Manual Professional Version: Melanoma. Clinical reference on melanoma risk factors, warning signs, and diagnosis.
- CMS: ICD-10 Codes, Code Tables, Index, and Official Guidelines. Official source for current ICD-10-CM files and guidelines used to verify codes.
Disclaimer: This article is for educational purposes and is not medical advice or a substitute for the official ICD-10-CM Official Guidelines for Coding and Reporting. Always verify codes against the current code set and follow your organization’s policies.
