melanoma

DEFINITION of melanoma

Melanoma is a highly aggressive malignant tumor originating from melanocytes — the neural crest-derived, pigment-producing cells found primarily in the basal layer of the epidermis. Unlike basal cell carcinoma and squamous cell carcinoma, melanoma carries significantly higher metastatic potential, capable of spreading via lymphatic and hematogenous routes to regional lymph nodes, lungs, liver, brain, and bone at an early stage. The underlying pathological mechanism involves mutations — most commonly in the BRAF, NRAS, and NF1 genes — that disrupt normal melanocyte differentiation and apoptosis, leading to unchecked proliferation of dysplastic pigmented cells. Melanoma may arise from pre-existing melanocytic nevi (physiological context) or de novo on normal skin (pathological context), and chronic ultraviolet radiation exposure is the primary environmental trigger. Clinically relevant subtypes include superficial spreading melanoma (most common; ~70% of cases), nodular melanoma (most aggressive; coded under C43.9 when site unspecified), lentigo maligna melanoma (sun-damaged skin of elderly patients), and acral lentiginous melanoma (palms, soles, subungual; disproportionately affects darker skin tones). Melanoma is commonly confused with dysplastic nevus (atypical mole) — the key distinction is that melanoma demonstrates frank malignant transformation with invasion of the dermis, while dysplastic nevi remain benign with cytologic atypia only.

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ETYMOLOGY of melanoma

greek latin

Component	Origin	Meaning
melan- / melano-	Greek melas (MEH-las), genitive melanos	”black,” “dark,” “dark-colored” — combining form referring to the dark pigment melanin produced by melanocytes
-oma	Greek -ōma (OH-mah), from -ōmat-, noun-forming suffix	Noun-forming suffix — “tumor,” “swelling,” “mass” — denotes an abnormal growth or neoplasm

The word entered English in the 1820s as melanoma (noun), coined in modern medical Latin from Greek melas (“black”) + -ōma (“tumor”) — literally “black tumor.” The root melas (“black, dark”) connects Melanoma to the entire melano- root family: melanin (melan + -in → the dark pigment itself), melanocyte (melano- + -cyte → the pigment-producing cell), and melanosis (melano + -osis → abnormal dark pigmentation). The combining form melano- appears broadly in medical terminology including melancholia (historically: “black bile” humor), melanocytosis (excess melanocytes), melanuria (dark pigment in urine), and melasma (patchy skin hyperpigmentation).

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🔀 ALIASES / ALTERNATE TERMS

• Melanomatous (adjective form — used clinically in collocations such as “melanomatous lesion,” “melanomatous nodule,” “melanomatous change”)
• Malignant melanoma (the full clinical term; used interchangeably with melanoma in oncology and dermatology settings — reflects explicit malignant behavior)
• Cutaneous melanoma (skin-specific form; the most common presentation; coded under C43.x — distinguishes from ocular and mucosal subtypes)
• Superficial spreading melanoma (most common subtype, ~70% of cases; radial growth phase predominates early; typically arises in pre-existing nevi)
• Nodular melanoma (aggressive vertical growth phase from onset; no radial growth phase; often amelanotic — coded under C43.9 or site-specific C43.x)
• Lentigo maligna melanoma (arises from lentigo maligna on chronically sun-damaged skin; slow-growing; most common in elderly patients on face/neck)
• Acral lentiginous melanoma (subtype on palms, soles, and subungual areas; not sun-related; coded under C43.6x or C43.7x depending on site)
• Amelanotic melanoma (pigment-poor or non-pigmented variant; frequently missed on clinical exam due to absent dark coloration; high misdiagnosis rate)
• Desmoplastic melanoma (rare, fibrotic, neurotropic subtype; high local recurrence; perineural invasion common; often appears scar-like)
• Ocular melanoma|Uveal melanoma (melanoma of the uveal tract — iris, ciliary body, choroid; coded separately under C69.3x-C69.4x — NOT under C43)
• Mucosal melanoma]] (arises in mucous membranes — nasal, oral, anorectal, genitourinary; coded to the specific mucosal site — NOT under C43)
• Melanoma in situ (pre-invasive melanoma confined to epidermis; EXCLUDED from C43 — coded under D03.x; Clark Level I)

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🔗 RELATED TERMS

• Melanocyte — the originating cell type of melanoma; a neural crest-derived, dendritic cell residing in the basal epidermis responsible for synthesizing and transferring melanin to keratinocytes
• Melanin — the dark biopolymer pigment produced by melanocytes via melanogenesis; gives skin, hair, and iris their color; shares the melan- root with melanoma
• Melanocytic nevus — a benign proliferation of melanocytes (common mole); serves as a precursor lesion in a subset of melanomas; distinguished from melanoma by lack of malignant invasion
• Dysplastic nevus — an atypical melanocytic nevus with architectural disorder and cytologic atypia; intermediate between a benign nevus and melanoma; marker of increased melanoma risk
• Melanoma in situ — the non-invasive precursor form of cutaneous melanoma; confined to the epidermis; coded under D03.x (EXCLUDES from C43); Clark Level I
• Lentigo maligna — a form of melanoma in situ on sun-damaged skin; coded D03.4 (face/neck); transforms into lentigo maligna melanoma when dermal invasion occurs
• BRAF mutation — the most common molecular driver of melanoma (~50% of cutaneous melanomas carry V600E mutation); target of BRAF inhibitors (vemurafenib, dabrafenib) used in systemic therapy
• Clark level — histological staging system describing depth of melanoma invasion into skin layers (I-V); used alongside Breslow thickness
• Breslow thickness — the most important prognostic factor in primary melanoma; measured in millimeters from granular layer to deepest tumor cell; drives surgical margin and sentinel lymph node biopsy decisions
• Sentinel lymph node biopsy — key staging procedure for melanoma >0.8 mm Breslow thickness; determines regional nodal involvement without full lymph node dissection
• Basal cell carcinoma — most common skin cancer; arises from basal keratinocytes (NOT melanocytes); rarely metastasizes; clinically distinguished from melanoma by pearly/translucent appearance and rolled borders
• Squamous cell carcinoma — second most common skin cancer; arises from squamous keratinocytes; more metastatic than BCC but less so than melanoma; coded under C44.x

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CODING CORNER

🏥 ICD-10-CM CODES

Malignant Melanoma of Skin — Primary Site (C43.x — Site-Specificity Required)

Code	Description
C43.0	Malignant melanoma of lip
C43.10	Malignant melanoma of unspecified eyelid, including canthus
C43.11	Malignant melanoma of right eyelid, including canthus
C43.111	Malignant melanoma of right upper eyelid, including canthus
C43.112	Malignant melanoma of right lower eyelid, including canthus
C43.12	Malignant melanoma of left eyelid, including canthus
C43.121	Malignant melanoma of left upper eyelid, including canthus
C43.122	Malignant melanoma of left lower eyelid, including canthus
C43.20	Malignant melanoma of unspecified ear and external auricular canal
C43.21	Malignant melanoma of right ear and external auricular canal
C43.22	Malignant melanoma of left ear and external auricular canal
C43.30	Malignant melanoma of unspecified part of face
C43.31	Malignant melanoma of nose
C43.39	Malignant melanoma of other parts of face
C43.4	Malignant melanoma of scalp and neck
C43.51	Malignant melanoma of anal skin
C43.52	Malignant melanoma of skin of breast
C43.59	Malignant melanoma of other part of trunk
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
C43.70	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

Melanoma In Situ — Pre-Invasive / Non-Billable as C43 (D03.x — Excluded from C43)

Code	Description
D03.0	Melanoma in situ of lip
D03.10	Melanoma in situ of unspecified eyelid, including canthus
D03.11	Melanoma in situ of right eyelid, including canthus
D03.12	Melanoma in situ of left eyelid, including canthus
D03.20	Melanoma in situ of unspecified ear and external auricular canal
D03.21	Melanoma in situ of right ear and external auricular canal
D03.22	Melanoma in situ of left ear and external auricular canal
D03.30	Melanoma in situ of unspecified part of face
D03.39	Melanoma in situ of other parts of face
D03.4	Melanoma in situ of scalp and neck
D03.51	Melanoma in situ of anal skin
D03.52	Melanoma in situ of breast (skin) (soft tissue)
D03.59	Melanoma in situ of other part of trunk
D03.60	Melanoma in situ of unspecified upper limb, including shoulder
D03.61	Melanoma in situ of right upper limb, including shoulder
D03.62	Melanoma in situ of left upper limb, including shoulder
D03.70	Melanoma in situ of unspecified lower limb, including hip
D03.71	Melanoma in situ of right lower limb, including hip
D03.72	Melanoma in situ of left lower limb, including hip
D03.8	Melanoma in situ of other sites
D03.9	Melanoma in situ, unspecified

Metastatic Melanoma — Secondary Sites

Code	Description
C77.0	Secondary and unspecified malignant neoplasm of lymph nodes of head, face and neck
C77.2	Secondary and unspecified malignant neoplasm of intra-abdominal lymph nodes
C77.3	Secondary and unspecified malignant neoplasm of axillary and upper limb lymph nodes
C77.4	Secondary and unspecified malignant neoplasm of inguinal and lower limb lymph nodes
C78.00	Secondary malignant neoplasm of unspecified lung
C78.01	Secondary malignant neoplasm of right lung
C78.02	Secondary malignant neoplasm of left lung
C79.31	Secondary malignant neoplasm of brain
C79.51	Secondary malignant neoplasm of bone
C79.89	Secondary malignant neoplasm of other specified sites

Personal/Family History & Surveillance

Code	Description
Z85.820	Personal history of malignant melanoma of skin
Z80.8	Family history of other conditions (use for family Hx of melanoma)
Z14.8	Genetic susceptibility to other malignant neoplasm (e.g., CDKN2A mutation carrier)

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🔧 COMMON CPT CODES (Melanoma-Related Diagnosis & Treatment)

CPT Code	Description
11102	Tangential (shave) biopsy of skin, single lesion — initial diagnostic biopsy for suspicious pigmented lesion
11104	Punch biopsy of skin (including simple closure), single lesion — preferred for full-thickness melanocytic assessment
11106	Incisional biopsy of skin (including simple closure), single lesion — used for larger pigmented lesions where excisional biopsy is not feasible
11600	Excision, malignant lesion including margins, trunk/arms/legs; excised diameter ≤0.5 cm
11601	Excision, malignant lesion including margins, trunk/arms/legs; excised diameter 0.6-1.0 cm
11602	Excision, malignant lesion including margins, trunk/arms/legs; excised diameter 1.1-2.0 cm
11603	Excision, malignant lesion including margins, trunk/arms/legs; excised diameter 2.1-3.0 cm
11604	Excision, malignant lesion including margins, trunk/arms/legs; excised diameter 3.1-4.0 cm
11605	Excision, malignant lesion including margins, trunk/arms/legs; excised diameter 4.1-5.0 cm
11606	Excision, malignant lesion including margins, trunk/arms/legs; excised diameter >5.0 cm
11640	Excision, malignant lesion including margins, face/ears/eyelids/nose/lips; excised diameter ≤0.5 cm
11641	Excision, malignant lesion including margins, face/ears/eyelids/nose/lips; excised diameter 0.6-1.0 cm
11642	Excision, malignant lesion including margins, face/ears/eyelids/nose/lips; excised diameter 1.1-2.0 cm
11643	Excision, malignant lesion including margins, face/ears/eyelids/nose/lips; excised diameter 2.1-3.0 cm
11644	Excision, malignant lesion including margins, face/ears/eyelids/nose/lips; excised diameter 3.1-4.0 cm
11646	Excision, malignant lesion including margins, face/ears/eyelids/nose/lips; excised diameter >4.0 cm
17311	Mohs micrographic surgery, head/neck/hands/feet/genitalia; first stage, up to 5 tissue blocks
17312	Mohs micrographic surgery, head/neck/hands/feet/genitalia; each additional stage, up to 5 tissue blocks (add-on)
17313	Mohs micrographic surgery, trunk/arms/legs; first stage, up to 5 tissue blocks
17314	Mohs micrographic surgery, trunk/arms/legs; each additional stage, up to 5 tissue blocks (add-on)
38500	Biopsy or excision of lymph node(s); open, superficial — used for regional node assessment
38900	Intraoperative identification (e.g., mapping) of sentinel lymph node(s) includes injection of non-radioactive dye (add-on)

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⚠️ Coding Note: Melanoma ICD-10-CM codes under C43 require site-specificity and laterality — never report the parent code C43 alone as it is not billable; always assign the most specific 4th, 5th, or 7th character code available (e.g., C43.112 for right lower eyelid). When melanoma has metastasized, sequence the primary site C43.x first, followed by the appropriate secondary malignancy code (C77.x, C78.x, or C79.x); however, if the patient is being treated only for the metastatic site, the secondary code may be sequenced first per ICD-10-CM sequencing guidelines. A critical undercoding alert: inpatient profee coders frequently miss capturing C43.52 (skin of breast) and C43.51 (anal skin) — watch for documentation phrases such as “perianal pigmented lesion,” “trunk melanoma,” or “chest wall skin lesion resected” as triggers to query for precise site confirmation. For CPT excision code selection (11600-11646), code selection is driven by the excised specimen diameter (including margins), NOT the clinical lesion size — always pull the pathology report for the final excised diameter before coding. Sentinel lymph node biopsy (38900 as add-on + 38500 for the open excision) requires separate documentation of the sentinel node mapping procedure; report 38900 in addition to the primary excision code. Modifier -59 may be required when biopsy (11102-11106) and definitive excision are performed on the same date by the same provider if payer policy flags the combination.

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DERIVATIONS of melanoma

TABLE definition AS Definition
FROM #medterm 
WHERE length(filter(roots, (word) => econtains([[Melanoma]].roots, word))) > 0 AND file.name != [[Melanoma]].file.name
SORT file.name ASC

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Query functionality

TABLE definition AS Definition
FROM #medterm 
WHERE length(filter(definition, (word) => econtains([[Melanoma]].definition, word))) > 0 AND file.name != [[Melanoma]].file.name

Med roots dictionary Appendix A Prefixes Appendix B Combining Forms Appendix C Suffixes Appendix D Suffix forms