2027 ICD-10-CM Diagnosis Code C44.509Unspecified malignant neoplasm of skin of other part of trunk

ICD-10-CM Codes›C00–D49›C43-C44›C44

ICD-10-CM C44.509
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

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 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

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.

  • 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

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to C44.509: its own notes plus those printed at C44.5, 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.

From C44 Other and unspecified malignant neoplasm of skin applies to 101 codes
  • 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.

From C44.5 Other and unspecified malignant neoplasm of skin of trunk applies to 12 codes
From C44 Other and unspecified malignant neoplasm of skin applies to 101 codes
  • Kaposi's sarcoma of skin (C46.0)
  • malignant melanoma of skin (C43.-)
  • malignant neoplasm of skin of genital organs (C51-C52, C60.-, C63.2)
  • Merkel cell carcinoma (C4A.-)

Notes

General instructions on how these codes are used.

From Chapter 2 (C00-D49) Neoplasms applies to 1,730 codes
  • 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 C44.509, its category, or a range that includes it.

Applicable To 1

These notes mention C44.509.

  • Z85.828 Personal history of other malignant neoplasm of skin
    Conditions classifiable to C44 names C44, which includes this code

Excludes1 1

These codes carry an Excludes1 note naming C44.509: they are not reported together with it, unless the two conditions are unrelated.

  • C76 Malignant neoplasm of other and ill-defined sites
    malignant neoplasm of skin (C44.-) names C44.-, which includes this code

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.

SiteMalig.
Primary		Malig.
Secondary		Ca
in situ		BenignUncertainUnspec.
abdomen, abdominal › wall [See Also: Neoplasm, abdomen, wall, skin]C44.509C79.2D04.5D23.5D48.5D49.2
abdomen, abdominal › wall [See Also: Neoplasm, abdomen, wall, skin] › skinC44.509–––––
axilla, axillary › fold [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2
nates [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2
skin NOS › abdominal wallC44.509C79.2D04.5D23.5D48.5D49.2
skin NOS › axilla, axillary fold [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2
skin NOS › back [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2
skin NOS › buttock [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2
skin NOS › chest (wall) [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2
skin NOS › clavicular area [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2
skin NOS › flank [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2
skin NOS › gluteal region [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2
skin NOS › groin [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2
skin NOS › infraclavicular region [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2
skin NOS › inguinal region [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2
skin NOS › nates [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2
skin NOS › pubes [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2
skin NOS › sacrococcygeal region [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2
skin NOS › scapular region [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2
skin NOS › submammary fold [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2
skin NOS › thoracic wall [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2
skin NOS › trunkC44.509C79.2D04.5D23.5D48.5D49.2
skin NOS › umbilicus [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2
umbilicus, umbilical [See Also: Neoplasm, skin, trunk]C44.509C79.2D04.5D23.5D48.5D49.2

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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About C44.509Overview

What is the ICD-10 code for unspecified malignant neoplasm of skin of other part of trunk?

The ICD-10-CM code for unspecified malignant neoplasm of skin of other part of trunk is C44.509 (sometimes written as C44509). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

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, 2026 through September 30, 2027.

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 607, 606, with relative weights from 0.8772 to 1.5721 depending on complications. Higher weights mean higher Medicare reimbursement.

Can C44.509 be reported with C21.0?

Not as a rule. The Excludes1 note at C44.5, which applies to C44.509, lists "anus NOS (C21.0)". 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 C44.509?

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.