2027 ICD-10-CM Diagnosis Code C43.8Malignant melanoma of overlapping sites of skin
ICD-10-CM Codes›C00–D49›C43-C44›C43
- Billable — Valid for Submission
- Risk Adjusts — HCC 23
- Chronic Condition
C43.8 is a billable ICD-10-CM diagnosis code for malignant melanoma of overlapping sites of skin. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 595 through 596. Coders also document this condition as overlapping malignant melanoma of skin. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Skin cancers - melanoma.
For Medicare Advantage risk adjustment, C43.8 maps to CMS-HCC Category 23 (Prostate, Breast, and Other Cancers and Tumors) under the V28 model, adding a risk factor of about 0.186 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Quality Payment Program MeasuresBilling
Medicare quality measures that can apply when C43.8 is part of the patient record.
Melanoma Reporting
High Priority: YES
Measure Type: Process
Submission Methods: Claims, Registry
Description: Pathology reports for primary malignant cutaneous melanoma that include the pT category, thickness, ulceration and mitotic rate, peripheral and deep margin status and presence or absence of microsatellitosis for invasive tumors.
Medicare Risk Adjustment (HCC)Billing
C43.8 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.
Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Overlapping malignant melanoma of skin
- Overlapping malignant neoplasm of skin
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to C43.8: its own notes plus those printed at C43 and Chapter 2. A note printed at a category, block or chapter applies to every code under it.
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
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 C43.8, its category, or a range that includes it.
Applicable To 1
These notes mention C43.8.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Cutaneous Melanoma
a primary melanoma arising from atypical melanocytes in the skin. precursor lesions include acquired and congenital melanocytic nevi, and dysplastic nevi. several histologic variants have been recognized, including superficial spreading melanoma, acral lentiginous melanoma, nodular melanoma, and lentigo maligna melanoma.
Patient EducationClinical
Melanoma
Melanoma is the most serious type of skin cancer. Often the first sign of melanoma is a change in the size, shape, color, or feel of a mole. Most melanomas have a black or black-blue area. Melanoma may also appear as a new mole. It may be black, abnormal, or "ugly looking."
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert C43.8 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C43.8Overview
What is the ICD-10 code for malignant melanoma of overlapping sites of skin?
The ICD-10-CM code for malignant melanoma of overlapping sites of skin is C43.8 (sometimes written as C438). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is C43.8 (Malignant melanoma of skin) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report malignant melanoma of overlapping sites of skin on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does C43.8 group to?
When malignant melanoma of overlapping sites of skin is the principal diagnosis on an inpatient stay, it groups to MS-DRG 596, 595, with relative weights from 1.1067 to 2.0230 depending on complications. Higher weights mean higher Medicare reimbursement.
Can C43.8 be reported with a code from D03?
Not as a rule. The Excludes1 note at C43, which applies to C43.8, lists "melanoma in situ (D03.-)". 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 C43.8?
Under the General Equivalence Mappings, malignant melanoma of overlapping sites of skin converts to ICD-9-CM 172.8 (malig melanoma skin NEC). The mapping is approximate, so confirm the match fits the documentation.
What HCC is C43.8?
C43.8 (malignant melanoma of overlapping sites of skin) maps to CMS-HCC Category 23 (Prostate, Breast, and Other Cancers and Tumors), commonly written as HCC 23, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 12 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 22.
Does C43.8 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, C43.8 adds a risk adjustment factor of about 0.186 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.186 to 0.237 depending on the payment segment). A more severe related category (HCC 17, HCC 18, HCC 19, HCC 20, HCC 21, and HCC 22) supersedes it when both are reported. See the full factor table on the HCC 23 category page.
