2023 ICD-10-CM Diagnosis Code C43.9

Malignant melanoma of skin, unspecified

    2016 2017 2018 2019 2020 2021 2022 2023 Billable/Specific Code
  • C43.9 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
  • The 2023 edition of ICD-10-CM C43.9 became effective on October 1, 2022.
  • This is the American ICD-10-CM version of C43.9 - other international versions of ICD-10 C43.9 may differ.
Applicable To
  • Malignant melanoma of unspecified site of skin
  • Melanoma (malignant) NOS
The following code(s) above C43.9 contain annotation back-references
Annotation Back-References
In this context, annotation back-references refer to codes that contain:
  • Applicable To annotations, or
  • Code Also annotations, or
  • Code First annotations, or
  • Excludes1 annotations, or
  • Excludes2 annotations, or
  • Includes annotations, or
  • Note annotations, or
  • Use Additional annotations
that may be applicable to C43.9:
  • C00-D49
    2023 ICD-10-CM Range C00-D49


    • 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).
  • C43
    ICD-10-CM Diagnosis Code C43

    Malignant melanoma of skin

      2016 2017 2018 2019 2020 2021 2022 2023 Non-Billable/Non-Specific Code
    Type 1 Excludes
    Type 2 Excludes
    • malignant melanoma of skin of genital organs (C51-C52, C60.-, C63.-)
    • Merkel cell carcinoma (C4A.-)
    • sites other than skin-code to malignant neoplasm of the site
    Malignant melanoma of skin
Approximate Synonyms
  • Acral lentiginous malignant melanoma of skin
  • Amelanotic malignant melanoma of skin
  • Carcinomatosis melanoma
  • Desmoplastic malignant melanoma
  • Lentigo maligna melanoma
  • Malignant melanoma of skin
  • Malignant melanoma of unknown origin
  • Melanoma
  • Melanoma, carcinomatosis
  • Melanoma, metastatic
  • Melanoma, metastatic to bilateral lungs
  • Melanoma, metastatic to bone
  • Melanoma, metastatic to kidney
  • Melanoma, metastatic to left lung
  • Melanoma, metastatic to liver
  • Melanoma, metastatic to lung
  • Melanoma, metastatic to lymph node
  • Melanoma, metastatic to pancreas
  • Melanoma, metastatic to right lung
  • Melanoma, metastatic to skin
  • Melanoma, skin, acrolentiginous
  • Melanoma, skin, amelanotic
  • Melanoma, skin, desmoplastic
  • Melanoma, skin, nodular
  • Melanoma, skin, superficial spreading
  • Melanoma, unknown primary
  • Metastatic malignant melanoma
  • Nodular malignant melanoma of skin
  • Secondary malignant melanoma of bilateral lungs
  • Secondary malignant melanoma of bone
  • Secondary malignant melanoma of kidney
  • Secondary malignant melanoma of left lung
  • Secondary malignant melanoma of liver
  • Secondary malignant melanoma of lung
  • Secondary malignant melanoma of lymph node
  • Secondary malignant melanoma of pancreas
  • Secondary malignant melanoma of right lung
  • Secondary malignant melanoma of skin
  • Superficial spreading malignant melanoma of skin
Clinical Information
  • 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.
ICD-10-CM C43.9 is grouped within Diagnostic Related Group(s) (MS-DRG v40.0):
  • 595 Major skin disorders with mcc
  • 596 Major skin disorders without mcc

Convert C43.9 to ICD-9-CM

Code History
  • 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
  • 2017 (effective 10/1/2016): No change
  • 2018 (effective 10/1/2017): No change
  • 2019 (effective 10/1/2018): No change
  • 2020 (effective 10/1/2019): No change
  • 2021 (effective 10/1/2020): No change
  • 2022 (effective 10/1/2021): No change
  • 2023 (effective 10/1/2022): No change

Diagnosis Index entries containing back-references to C43.9:

ICD-10-CM Codes Adjacent To C43.9
C43.59 Malignant melanoma of other part of trunk
C43.6 Malignant melanoma of upper limb, including shoulder
C43.60 Malignant melanoma of unspecified upper limb, including shoulder
C43.61 Malignant melanoma of right upper limb, including shoulder
C43.62 Malignant melanoma of left upper limb, including shoulder
C43.7 Malignant melanoma of lower limb, including hip
C43.70 Malignant melanoma of unspecified lower limb, including hip
C43.71 Malignant melanoma of right lower limb, including hip
C43.72 Malignant melanoma of left lower limb, including hip
C43.8 Malignant melanoma of overlapping sites of skin
C43.9 Malignant melanoma of skin, unspecified
C4A Merkel cell carcinoma
C4A.0 Merkel cell carcinoma of lip
C4A.1 Merkel cell carcinoma of eyelid, including canthus
C4A.10 Merkel cell carcinoma of unspecified eyelid, including canthus
C4A.11 Merkel cell carcinoma of right eyelid, including canthus
C4A.111 Merkel cell carcinoma of right upper eyelid, including canthus
C4A.112 Merkel cell carcinoma of right lower eyelid, including canthus
C4A.12 Merkel cell carcinoma of left eyelid, including canthus
C4A.121 Merkel cell carcinoma of left upper eyelid, including canthus
C4A.122 Merkel cell carcinoma of left lower eyelid, including canthus

Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.