2026 ICD-10-CM Diagnosis Code C44.99Other specified malignant neoplasm of skin, unspecified

ICD-10-CM Codes›C00–D49›C43-C44›C44

ICD-10-CM C44.99
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

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 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

ICD-10-CM Code
C44.99
Billable Status
Yes — Valid for Submission
Code Describes
Other specified malignant neoplasm of skin, unspecified
Short Description
Other specified malignant neoplasm of skin, unspecified
Same as the full description in the CMS dataset.
Parent Code
C44.9
Other and unspecified malignant neoplasm of skin, unspecified

Code Classification

ChapterC00–D49Neoplasms
SectionC43-C44Melanoma and other malignant neoplasms of skin
CategoryC44Other and unspecified malignant neoplasm of skin
This CodeC44.99Other specified malignant neoplasm of skin, unspecified

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
  • Lymphoepithelial tumor of skin
  • 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

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Adenocarcinoma
      • apocrine
        • unspecified site
    • Carcinoma(malignant)
      • apocrine
        • unspecified site

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NEO028
Skin cancers - all other types
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Dermatofibrosarcoma

    a sarcoma of the deep layers of the skin. the tumors are locally aggressive tends to recur but rarely metastatic. it can be classified into variants depending on the cell type tumors are derived from or by its characteristics: pigmented variant from melanin-containing dermal dendritic cells; myxoid variant, myxoid stromal cells; giant cell variant characterized by giant cells in the tumors; and fibrosarcomatous variant chracterized by tumor areas histologically indistinguishable from fibrosarcoma.

  • Fibrosarcoma

    a sarcoma derived from deep fibrous tissue, characterized by bundles of immature proliferating fibroblasts with variable collagen formation, which tends to invade locally and metastasize by the bloodstream. (stedman, 25th ed)

  • Eccrine Porocarcinoma

    a rare malignant neoplasm of the sweat glands. it most often develops as a form of degenerative progression from a benign eccrine poroma.

  • Myxoid Dermatofibrosarcoma Protuberans

    a morphologic variant of dermatofibrosarcoma protuberans characterized by the presence of extensive myxoid stroma formation and a storiform growth pattern.

  • Metastatic Basal Cell Carcinoma

    a carcinoma that arises from the basal cells and has metastasized to another anatomic site.

Table of NeoplasmsClinical

Anatomical sites in the Table of Neoplasms that reference this code family.

SiteMalig.
Primary		Malig.
Secondary		Ca
in situ		BenignUncertainUnspec.
skin NOS › specified type NECC44.99–––––

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.

ICD-9-CM
173.99 Oth mal neo skn site NOS
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About C44.99Overview

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, 2025 through September 30, 2026.

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 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 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.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.