2026 ICD-10-CM Diagnosis Code D04.9Carcinoma in situ of skin, unspecified
ICD-10-CM Codes›C00–D49›D00-D09›D04
- Billable — Valid for Submission
- Not Chronic
D04.9 is a billable ICD-10-CM diagnosis code for carcinoma in situ of skin, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 606 through 607. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Skin cancers - all other types.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Atrophic squamous cell carcinoma in situ of skin
- Basal cell carcinoma of skin in situ
- Carcinoma in situ of adnexa of skin
- Carcinoma in situ of sebaceous gland
- Carcinoma in situ of skin
- Carcinoma in situ of surface epithelium
- Carcinoma in situ of sweat gland
- Clear cell squamous cell carcinoma in situ of skin
- Clonal squamous cell carcinoma in situ of skin
- Multiple squamous cell carcinoma in situ of skin
- Pagetoid squamous cell carcinoma in situ of skin
- Pigmented squamous cell carcinoma in situ of skin
- Porocarcinoma in situ
- Psoriasiform squamous cell carcinoma in situ of skin
- Squamous cell carcinoma in situ of skin
- Squamous cell carcinoma in situ of skin caused by sunlight
- Verrucous squamous cell carcinoma in situ of skin
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
- Adenocarcinoma - See Also: Neoplasm, malignant, by site;
- apocrine
- in situ
- unspecified site - D04.9
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index.
- Adenocarcinoma
- apocrine
- in situ
- unspecified site
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Table of NeoplasmsClinical
Anatomical sites in the Table of Neoplasms that reference this code family.
| Site | Malig. Primary | Malig. Secondary | Ca in situ | Benign | Uncertain | Unspec. |
|---|---|---|---|---|---|---|
| connective tissue NEC › skin (dermis) NEC [See Also: Neoplasm, skin, by site] | C44.90 | C79.2 | D04.9 | D23.9 | D48.5 | D49.2 |
| nail [See Also: Neoplasm, skin, limb] | C44.90 | C79.2 | D04.9 | D23.9 | D48.5 | D49.2 |
| scar NEC [See Also: Neoplasm, skin, by site] | C44.90 | C79.2 | D04.9 | D23.9 | D48.5 | D49.2 |
| skin NOS | C44.90 | C79.2 | D04.9 | D23.9 | D48.5 | D49.2 |
| skin NOS › limb NEC | C44.90 | C79.2 | D04.9 | D23.9 | D48.5 | D49.2 |
| sudoriferous, sudoriparous gland, site unspecified | C44.90 | C79.2 | D04.9 | D23.9 | D48.5 | D49.2 |
| sweat gland (apocrine) (eccrine), site unspecified | C44.90 | C79.2 | D04.9 | D23.9 | D48.5 | D49.2 |
Patient EducationClinical
Skin Cancer
Skin cancer is the most common form of cancer in the United States. The two most common types are basal cell cancer and squamous cell cancer. They usually form on the head, face, neck, hands, and arms. Another type of skin cancer, melanoma, is more dangerous but less common.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert D04.9 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About D04.9Overview
Is D04.9 (Carcinoma in situ of skin) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report carcinoma in situ of skin, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does D04.9 group to?
When carcinoma in situ of skin, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 606, 607, with relative weights from 0.9064 to 1.5132 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of D04.9?
Under the General Equivalence Mappings, carcinoma in situ of skin, unspecified converts to ICD-9-CM 232.9 (ca in situ skin NOS). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.
