2027 ICD-10-CM Diagnosis Code C44.99Other specified malignant neoplasm of skin, unspecified
ICD-10-CM Codes›C00–D49›C43-C44›C44
- Billable — Valid for Submission
- Chronic Condition
C44.99 is a billable ICD-10-CM diagnosis code for other specified malignant neoplasm of skin, unspecified. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) 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.
- Adenoid cystic eccrine carcinoma of skin
- Angiosarcoma of skin
- Apocrine adenocarcinoma of skin
- Basal cell carcinoma with adnexal differentiation
- Basal cell carcinoma with eccrine differentiation
- Basosquamous carcinoma of skin
- Carcinosarcoma of skin
- Clear cell eccrine hidradenocarcinoma
- Cutaneous fibrosarcoma
- Dermatofibrosarcoma protuberans
- Dermatofibrosarcoma protuberans with giant cell fibroblastoma
- Dermatofibrosarcoma protuberans with granular cell change
- Dermatofibrosarcoma protuberans with myoid differentiation
- Digital papillary eccrine carcinoma of skin
- Eccrine carcinoma of skin
- Eccrine ductal carcinoma
- Eccrine porocarcinoma
- Endocrine mucin-producing sweat gland carcinoma
- Epithelioid cell sarcoma of skin
- Epithelioid sarcoma
- Extramammary Paget's disease of skin
- Fibrosarcoma
- Fibrosarcomatous dermatofibrosarcoma protuberans
- Giant cell malignant fibrous histiocytoma of skin
- Hidradenocarcinoma
- Infantile fibrosarcoma
- Inflammatory malignant fibrous histiocytoma of skin
- Keratinocytic epidermal carcinoma of skin
- Localized malignant reticulohistiocytoma
- Malignant chondroid syringoma
- Malignant cylindroma
- Malignant eccrine spiradenoma
- Malignant fibrohistiocytic tumor of skin
- Malignant hemangiopericytoma of skin
- Malignant neoplasm of skin with pilar differentiation
- Malignant skin tumor with apocrine differentiation
- Metastatic adenocarcinoma to skin
- Metastatic apocrine adenocarcinoma
- Metastatic basal cell carcinoma
- Metastatic basosquamous cell carcinoma to skin
- Metastatic eccrine porocarcinoma
- Metastatic malignant neoplasm to adnexa of skin
- Metastatic malignant neoplasm to conjunctiva
- Metastatic malignant neoplasm to sebaceous gland
- Metastatic pilomatrix carcinoma
- Metastatic sebaceous adenocarcinoma
- Metastatic sebaceous adenocarcinoma to eyelid
- Microcystic adnexal carcinoma
- Mixed eccrine/pilar adnexal carcinoma of skin
- Mucinous eccrine carcinoma of skin
- Mucoepidermoid carcinoma of skin
- Muir-Torré syndrome
- Myxofibrosarcoma of skin
- Myxoid dermatofibrosarcoma protuberans
- Peripheral neuroepithelioma
- Pigmented dermatofibrosarcoma protuberans of skin
- Pilomatrix carcinoma of skin
- Plaque-like dermatofibrosarcoma protuberans
- Pleomorphic malignant fibrous histiocytoma of skin
- Primary adenocarcinoma of skin
- Primary adenoid cystic eccrine carcinoma of skin
- Primary adnexal carcinoma of skin
- Primary apocrine adenocarcinoma of skin
- Primary carcinosarcoma of skin
- Primary clear cell eccrine hidradenocarcinoma
- Primary cutaneous fibrosarcoma
- Primary digital papillary eccrine carcinoma of skin
- Primary eccrine carcinoma of skin
- Primary eccrine ductal carcinoma
- Primary eccrine porocarcinoma
- Primary epithelioid cell sarcoma of skin
- Primary epithelioid sarcoma
- Primary extramammary Paget disease of skin
- Primary giant cell malignant fibrous histiocytoma of skin
- Primary infantile fibrosarcoma
- Primary inflammatory malignant fibrous histiocytoma of skin
- Primary malignant chondroid syringoma
- Primary malignant eccrine spiradenoma
- Primary malignant fibrous histiocytoma of skin
- Primary malignant neoplasm of sebaceous gland
- Primary malignant neoplasm of sweat gland
- Primary malignant sarcoma of skin
- Primary microcystic adnexal carcinoma
- Primary mixed eccrine/pilar adnexal carcinoma of skin
- Primary mucinous eccrine carcinoma of skin
- Primary mucoepidermoid carcinoma of skin
- Primary myxofibrosarcoma
- Primary myxofibrosarcoma of skin
- Primary pilomatrix carcinoma of skin
- Primary pleomorphic malignant fibrous histiocytoma of skin
- Primary sebaceous adenocarcinoma
- Primary signet ring cell carcinoma of skin
- Primary small cell eccrine carcinoma
- Primary superficial malignant fibrous histiocytoma of skin
- Primary undifferentiated adnexal carcinoma of skin
- Sebaceous adenocarcinoma
- Sebaceous adenocarcinoma of eyelid
- Small cell eccrine carcinoma
- Superficial malignant fibrous histiocytoma of skin
- Torré-Muir syndrome co-occurrent with malignant sebaceous neoplasm
- Trichilemmal carcinoma
- Undifferentiated adnexal carcinoma of skin
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to C44.99: its own notes plus those printed at C44 and Chapter 2. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- malignant neoplasm of sebaceous glands
- malignant neoplasm of sweat glands
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
Notes
General instructions on how these codes are used.
- Functional activity
- All neoplasms are classified in this chapter, whether they are functionally active or not. An additional code from Chapter 4 may be used, to identify functional activity associated with any neoplasm.
- Morphology [Histology]
- Chapter 2 classifies neoplasms primarily by site (topography), with broad groupings for behavior, malignant, in situ, benign, etc. The Table of Neoplasms should be used to identify the correct topography code. In a few cases, such as for malignant melanoma and certain neuroendocrine tumors, the morphology (histologic type) is included in the category and codes.
- Primary malignant neoplasms overlapping site boundaries
- A primary malignant neoplasm that overlaps two or more contiguous (next to each other) sites should be classified to the subcategory/code .8 ('overlapping lesion'), unless the combination is specifically indexed elsewhere. For multiple neoplasms of the same site that are not contiguous, such as tumors in different quadrants of the same breast, codes for each site should be assigned.
- Malignant neoplasm of ectopic tissue
- Malignant neoplasms of ectopic tissue are to be coded to the site mentioned, e.g., ectopic pancreatic malignant neoplasms are coded to pancreas, unspecified (C25.9).
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name C44.99, its category, or a range that includes it.
Applicable To 1
These notes mention C44.99.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Adenocarcinoma See Also: Neoplasm, malignant, by site;
unspecified site C44.99
Carcinoma (malignant) See Also: Neoplasm, by site, malignant;
unspecified site C44.99
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. |
|---|---|---|---|---|---|---|
| skin NOS › specified type NEC | C44.99 | – | – | – | – | – |
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 C44.99 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C44.99Overview
What is the ICD-10 code for other specified malignant neoplasm of skin, unspecified?
The ICD-10-CM code for other specified malignant neoplasm of skin, unspecified is C44.99 (sometimes written as C4499). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is C44.99 a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report other specified malignant neoplasm of skin, unspecified on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does C44.99 group to?
When other specified malignant neoplasm of skin, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 607, 606, with relative weights from 0.8772 to 1.5721 depending on complications. Higher weights mean higher Medicare reimbursement.
Can C44.99 be reported with C46.0?
Not as a rule. The Excludes1 note at C44, which applies to C44.99, lists "Kaposi's sarcoma of skin (C46.0)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
What is the ICD-9 equivalent of C44.99?
Under the General Equivalence Mappings, other specified malignant neoplasm of skin, unspecified converts to ICD-9-CM 173.99 (oth mal neo skn site NOS). The mapping is a direct match.
