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Melanoma - Basics & Bad Seeds

  • Malignant tumor of melanocytes; commonest skin cancer causing death.
  • Etiology: UV radiation (UVB > UVA) is the primary modifiable risk factor, causing DNA damage. UV radiation and melanoma development pathway
  • Risk Factors:
    • Sun exposure (intense, intermittent > chronic).
    • Fair skin, >50 common nevi, atypical nevi.
    • Family history (e.g., FAMMM syndrome, CDKN2A gene).
    • Immunosuppression.
  • Indian Context: Acral lentiginous melanoma (palms, soles, subungual) is more prevalent.

⭐ Intermittent, intense sun exposure is a higher risk factor for melanoma development than chronic, cumulative exposure.

Melanoma - Rogue Cells & Faces

  • Pathogenesis: Key mutations: BRAF, NRAS, c-KIT. Growth phases: Radial (intraepidermal) then Vertical (invasive, ↑metastatic potential).
  • Precursor Lesions: Giant congenital nevi (>20cm), dysplastic nevi.
  • Major Clinicopathological Types: 📌 Superficial Nodules Linger Around Amelanotic spots.
    • Superficial Spreading (SSM): Most common overall.
    • Nodular (NM): Worst prognosis, rapid vertical growth.
    • Lentigo Maligna Melanoma (LMM): Elderly, sun-exposed areas.
    • Acral Lentiginous Melanoma (ALM): Palms, soles, subungual; common in darker skin.
    • Amelanotic Melanoma: Difficult diagnosis, lacks pigment. Melanoma types and locations

⭐ Nodular melanoma has no significant radial growth phase, presenting early with vertical growth.

Melanoma - Spotting the Enemy

  • Clinical Clues: New/changing mole; symptoms like itching, bleeding.
  • ABCDE Rule (📌):
    • Asymmetry
    • Border irregularity
    • Color variegation (multiple shades)
    • Diameter >6mm
    • Evolving/Elevation (change in size, shape, color, elevation) Melanoma ABCDE & 7-point checklist
  • Glasgow 7-Point Checklist:
    • Major (3): Change in size, shape, color.
    • Minor (4): Diameter >6mm, inflammation, oozing/bleeding, altered sensation.
  • Diagnosis:
    • Dermoscopy for initial evaluation.
    • Excisional biopsy (gold standard) with 1-3mm margins for suspicious lesions. Avoid shave/punch biopsy.

⭐ Excisional biopsy is the diagnostic procedure of choice for a suspected melanoma.

Melanoma - Sizing Up Trouble

  • Microstaging: Key for prognosis.
    • Breslow Thickness: Depth in mm; most crucial prognostic factor.
    • Clark Level: Anatomical invasion level; less used now.
  • TNM Staging (AJCC 8th Ed.): Guides treatment.
    • T: Tumor thickness (Breslow), ulceration.
    • N: Nodal involvement (number, burden).
    • M: Distant metastasis.
  • Key Prognostic Factors:
    • Breslow depth, ulceration, mitotic rate.
    • Lymph node status, distant metastasis, LDH levels.
  • Sentinel Lymph Node Biopsy (SLNB):
    • Indications: Breslow >1mm, OR Breslow >0.8mm if ulceration/high mitotic rate present.

⭐ Breslow thickness is the single most important prognostic factor in localized melanoma.

Melanoma Staging: Clark Level & Breslow Thickness

Melanoma - Battle Plan Alpha

Multidisciplinary team essential.

  • Surgical Management: Wide Local Excision (WLE) primary. Margins by Breslow depth:
    • In situ: 0.5-1cm
    • <1mm: 1cm
    • 1-2mm: 1-2cm
    • 2mm: 2cm

  • Adjuvant Therapy (High-risk: Stage IIB/C, III):
    • Immunotherapy (Nivolumab, Pembrolizumab)
    • Targeted (BRAF V600): Dabrafenib/Trametinib
  • Metastatic (Stage IV): Systemic therapy (Immunotherapy, Targeted). Chemo limited.
  • Radiotherapy: Palliative; adjuvant in select cases.

⭐ For BRAF V600-mutated metastatic melanoma, combination BRAF/MEK inhibitors show improved outcomes over BRAF inhibitor monotherapy.

High-Yield Points - ⚡ Biggest Takeaways

  • Breslow thickness: Single most important prognostic factor.
  • ABCDE criteria: For clinical diagnosis (Asymmetry, Border, Color, Diameter >6mm, Evolving).
  • Superficial Spreading Melanoma: Most common subtype.
  • Acral Lentiginous Melanoma: Common in dark skin (palms, soles, nail beds).
  • Nodular Melanoma: Worst prognosis due to rapid vertical growth.
  • BRAF V600E mutation: Key therapeutic target.
  • Sentinel Lymph Node Biopsy (SLNB): For tumors >1mm or ulcerated_

Practice Questions: Melanoma

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What is the standard excision margin for thick melanomas (>2 mm Breslow thickness)?

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Flashcards: Melanoma

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Regarding the incidence of the three main types of skin cancer in the United States, _____ > Squamous >> Melanoma

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Regarding the incidence of the three main types of skin cancer in the United States, _____ > Squamous >> Melanoma

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