2026 ICD-10-CM Diagnosis Code C44.509Unspecified malignant neoplasm of skin of other part of trunk

Billable — Valid for Submission
Chronic Condition

ICD-10-CM C44.509

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

C44.509 is a billable ICD-10-CM diagnosis code for unspecified malignant neoplasm of skin of other part of trunk. 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

C44.509

Billable Status

Yes — Valid for Submission

Code Describes

Unspecified malignant neoplasm of skin of other part of trunk

Short Description

Unsp malignant neoplasm of skin of other part of trunk

Parent Code

C44.50

Unspecified malignant neoplasm of skin of trunk

Code Classification

ChapterC00–D49Neoplasms

SectionC43-C44Melanoma and other malignant neoplasms of skin

CategoryC44Other and unspecified malignant neoplasm of skin

This CodeC44.509Unspecified malignant neoplasm of skin of other part of trunk

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

Filter synonyms:

Carcinoma of skin of trunk
Malignant neoplasm of skin of abdominal wall
Malignant neoplasm of skin of axillary fold
Malignant neoplasm of skin of scapular region
Malignant neoplasm of skin of trunk
Malignant neoplasm of soft tissue of axilla
Malignant neoplasm of soft tissue of buttock
Neoplasm of skin of axilla
Neoplasm of skin of buttock
Neoplasm of skin of groin
Neoplasm of skin of umbilicus
Primary carcinoma of skin of trunk
Primary malignant neoplasm of axilla
Primary malignant neoplasm of inguinal region
Primary malignant neoplasm of skin of abdomen
Primary malignant neoplasm of skin of axilla
Primary malignant neoplasm of skin of back
Primary malignant neoplasm of skin of buttock
Primary malignant neoplasm of skin of chest
Primary malignant neoplasm of skin of groin
Primary malignant neoplasm of skin of trunk
Primary malignant neoplasm of skin of umbilicus
Primary malignant neoplasm of soft tissues of axilla
Primary malignant neoplasm of soft tissues of buttock

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

Table of NeoplasmsClinical

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

Filter table of neoplasms:

Site	Malig. Primary	Malig. Secondary	Ca in situ	Benign	Uncertain	Unspec.
abdomen, abdominal › wall [See Also: Neoplasm, abdomen, wall, skin]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
axilla, axillary › fold [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
nates [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
skin NOS › abdominal wall	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
skin NOS › axilla, axillary fold [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
skin NOS › back [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
skin NOS › buttock [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
skin NOS › chest (wall) [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
skin NOS › clavicular area [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
skin NOS › flank [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
skin NOS › gluteal region [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
skin NOS › groin [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
skin NOS › infraclavicular region [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
skin NOS › inguinal region [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
skin NOS › nates [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
skin NOS › pubes [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
skin NOS › sacrococcygeal region [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
skin NOS › scapular region [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
skin NOS › submammary fold [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
skin NOS › thoracic wall [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
skin NOS › trunk	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
skin NOS › umbilicus [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	D48.5	D49.2
umbilicus, umbilical [See Also: Neoplasm, skin, trunk]	C44.509	C79.2	D04.5	D23.5	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 C44.509 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM

173.50 Malig neo skin trunk NOS

Approximate The match is approximate rather than exact.

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 C44.509Overview

Is C44.509 (Unspecified malignant neoplasm of skin of trunk) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report unspecified malignant neoplasm of skin of other part of trunk on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does C44.509 group to?

When unspecified malignant neoplasm of skin of other part of trunk 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 C44.509?

Under the General Equivalence Mappings, unspecified malignant neoplasm of skin of other part of trunk converts to ICD-9-CM 173.50 (malig neo skin trunk NOS). The mapping is approximate, so confirm the match fits the documentation.

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.

Indicator	Meaning	CMS pays CC/MCC DRG
Y	Diagnosis was present at the time of inpatient admission	Yes
N	Diagnosis was not present at the time of admission	No
U	Documentation is insufficient to determine	No
W	Clinically undetermined	Yes
1	Unreported, exempt from POA reporting	No