ICD10BillableValid for clinical use

ICD-10 Code C43.121: Malignant melanoma of left upper eyelid, including canthus

C43.121 is a billable ICD-10 diagnosis code used to classify Malignant melanoma of left upper eyelid, including canthus in medical records and claims. You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records. ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Neoplasms (C00-D49).

Reviewed by HealthAssure Clinical TeamUpdated 26 May 2026

What is this code?

ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Neoplasms (C00-D49).

When is it used?

  • May be used when a clinician documents malignant melanoma of left upper eyelid, including canthus in a patient's medical record.
  • May appear in hospital records, claims, referrals, and clinical documentation.
  • This code can be used as a clinically usable diagnosis entry in standardized coding workflows.

What it does not mean

  • A code alone does not explain severity, treatment plan, or outcome.
  • A medical code should not be treated as a substitute for a doctor's diagnosis or advice.

Code hierarchy

chapter
2Neoplasms (C00-D49)
block
C00-C96Malignant neoplasms
block
C00-C75Malignant neoplasms, stated or presumed to be primary (of specified sites), and certain specified histologies, except neuroendocrine, and of lymphoid, hematopoietic and related tissue
block
C43-C44Melanoma and other malignant neoplasms of skin
category
C43Malignant melanoma of skin
category
C43.1Malignant melanoma of eyelid, including canthus
category
C43.12Malignant melanoma of left eyelid, including canthus
currentC43.12

Where you may see this code

You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.

Related specialists

OncologistGeneral PhysicianOphthalmologist

Coverage-related procedures and services

CPT 81479high
UNLISTED MOLECULAR PATHOLOGY PROCEDURE
Source: CMS coverage guidance
CPT 81445high
SOLID ORGAN NEOPLASM, GENOMIC SEQUENCE ANALYSIS PANEL, 5-50 GENES, INTERROGATION FOR SEQUENCE VARIANTS AND COPY NUMBER VARIANTS OR REARRANGEMENTS, IF PERFORMED; DNA ANALYSIS OR COMBINED DNA AND RNA ANALYSIS
Source: CMS coverage guidance
CPT 17315high
MOHS MICROGRAPHIC TECHNIQUE, INCLUDING REMOVAL OF ALL GROSS TUMOR, SURGICAL EXCISION OF TISSUE SPECIMENS, MAPPING, COLOR CODING OF SPECIMENS, MICROSCOPIC EXAMINATION OF SPECIMENS BY THE SURGEON, AND HISTOPATHOLOGIC PREPARATION INCLUDING ROUTINE STAIN(S) (EG, HEMATOXYLIN AND EOSIN, TOLUIDINE BLUE), EACH ADDITIONAL BLOCK AFTER THE FIRST 5 TISSUE BLOCKS, ANY STAGE (LIST SEPARATELY IN ADDITION TO CODE FOR PRIMARY PROCEDURE)
Source: CMS coverage guidance
CPT 17312high
MOHS MICROGRAPHIC TECHNIQUE, INCLUDING REMOVAL OF ALL GROSS TUMOR, SURGICAL EXCISION OF TISSUE SPECIMENS, MAPPING, COLOR CODING OF SPECIMENS, MICROSCOPIC EXAMINATION OF SPECIMENS BY THE SURGEON, AND HISTOPATHOLOGIC PREPARATION INCLUDING ROUTINE STAIN(S) (EG, HEMATOXYLIN AND EOSIN, TOLUIDINE BLUE), HEAD, NECK, HANDS, FEET, GENITALIA, OR ANY LOCATION WITH SURGERY DIRECTLY INVOLVING MUSCLE, CARTILAGE, BONE, TENDON, MAJOR NERVES, OR VESSELS; EACH ADDITIONAL STAGE AFTER THE FIRST STAGE, UP TO 5 TISSUE BLOCKS (LIST SEPARATELY IN ADDITION TO CODE FOR PRIMARY PROCEDURE)
Source: CMS coverage guidance
CPT 17311high
MOHS MICROGRAPHIC TECHNIQUE, INCLUDING REMOVAL OF ALL GROSS TUMOR, SURGICAL EXCISION OF TISSUE SPECIMENS, MAPPING, COLOR CODING OF SPECIMENS, MICROSCOPIC EXAMINATION OF SPECIMENS BY THE SURGEON, AND HISTOPATHOLOGIC PREPARATION INCLUDING ROUTINE STAIN(S) (EG, HEMATOXYLIN AND EOSIN, TOLUIDINE BLUE), HEAD, NECK, HANDS, FEET, GENITALIA, OR ANY LOCATION WITH SURGERY DIRECTLY INVOLVING MUSCLE, CARTILAGE, BONE, TENDON, MAJOR NERVES, OR VESSELS; FIRST STAGE, UP TO 5 TISSUE BLOCKS
Source: CMS coverage guidance
CPT 17314high
MOHS MICROGRAPHIC TECHNIQUE, INCLUDING REMOVAL OF ALL GROSS TUMOR, SURGICAL EXCISION OF TISSUE SPECIMENS, MAPPING, COLOR CODING OF SPECIMENS, MICROSCOPIC EXAMINATION OF SPECIMENS BY THE SURGEON, AND HISTOPATHOLOGIC PREPARATION INCLUDING ROUTINE STAIN(S) (EG, HEMATOXYLIN AND EOSIN, TOLUIDINE BLUE), OF THE TRUNK, ARMS, OR LEGS; EACH ADDITIONAL STAGE AFTER THE FIRST STAGE, UP TO 5 TISSUE BLOCKS (LIST SEPARATELY IN ADDITION TO CODE FOR PRIMARY PROCEDURE)
Source: CMS coverage guidance

Coding guidelines

Common synonyms

Malignant melanoma of left upper eyelid, including canthus

Frequently asked questions

Code details

CodeC43.121
SystemICD10
Display nameMalignant melanoma of left upper eyelid, including canthus
ChapterNeoplasms (C00-D49)
BlockMelanoma and other malignant neoplasms of skin

Flags

BillableYes
Valid clinical useYes

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.

ICD-10 Code C43.121 for Malignant melanoma of left upper eyelid, including canthus | HealthAssure