Skin Cancer

Skin Cancer

Types of Skin Cancer:

  1. Basal Cell Carcinoma: 80% – (90% appear of the face, ears, neck, and head – true for nodular BCC and sclerosing Superficial BCC most often on trunk and extremities)
    • Most common type of skin cancer
    • Most important risk factors: sun exposure, family Hx, and skin type
    • Incidence of these cancers increase with age due to cumulative sun exposure.
    • Types of BCC:
      • Nodular BCC (most common)
        • Micronodular
        • Pattern: raised, pearly white, smooth, translucent surface with telangiestasias
          • Smooth surface with loss of the normal pore pattern, may ulcerate with a blood crust.
        • Shave biopsy: shows lesions to be BCC
          • Mohs micrographic surgery: best Tx to produce the highest cure rate and best cosmetic result
        • Dx BCC:
          • Shave biopsy: Nodular BCC and Superficial BCC
          • Punch biopsy: Sclerosing BCC
        • Tx BCC:
          • Electro-desiccation and curettage
          • Cryotherapy with 3-5mm margins
          • Excision with 3-5mm margins
          • Mohs micrographic surgery:
            • Removal of tumor by scalpel in sequential horizontal layers
            • Each tissue sample is frozen, stained, and microscopically examined.
            • Repeated until all of the margins are clear.
            • Treat of choice for BCCs with poorly defined margins
              1. Especially those on the nose or eyelids, recurrent BCC on the face.
            • Imiquimod for superficial BCC
            • Vismodegib (locally advanced and metastatic BCC)
              • Basal Cell Nevus Syndrome – face covered in lesions
            • Radiation therapy
          • Superficial BCC
            • Pattern: Pink scaling plaques, thready border (slightly raised and pearly), occasionally they have shallow erosions or crusts.
          • Sclerosing and infiltrating BCC (least common)
            • Pattern: Ivory or colorless, flat or atrophic, indurated, may resemble scars. Called morpheaform b/c of their resemblance to localized scleroderma.
          • Pigmented BCC: May look like melanoma, increased pigment.
  1. Squamous Cell Carcinoma: 16% – same locations as BCC (esp. lips, ears, and scalp)
    • Bowen’s disease:
      • SCC in situ
      • Mainly in sun-exposed areas
      • Slightly elevated red scaly plaque with well-demarcated borders.
    • SCC with an increased risk of metastasis: larger advanced lesions, SCC on mucous membranes (in the oral cavity, on the lips), SCC on the ears, SCC arising in burn.
    • Tx options for SCC:
      • Excision with 4-6mm margin
      • Mohs for SCC with perineural invasion, recurrent SCC, and areas of functional and cosmetic importance.
      • SCC in situ only:
        • Curettage and desiccation after a shave biopsy
        • Cryotherapy – deep and wide freeze with 5mm margin.
  1. Melanoma: 4%
    • ABCDE’s of Melanoma:
      • A: Asymmetry
      • B: Border irregularity
      • C: Color variation
      • D: Diameter > 6mm (pencil eraser)
      • E: Evolving
    • Types of Melanoma:
      • Superficial spreading Melanoma (most common: 70%)
      • Nodular Melanoma: 15-30%
        • E, F, G of Melanoma – helps for Nodular Melanomas that may not have any of the other ABCDE criteria:
          • E: Elevated
          • F: Firm
          • G: Growing
        • Beware of the pink lump: Amelanotic
        • Never monitor an elevated nodule:
          • Nodular melanoma grow fast and deep
          • Do an immediate biopsy
          • Referral can lead to an unacceptable delay
        • Lentigo maligna Melanoma: 4-15%
          • Biopsy method: broad shave biopsy
        • Acral lentiginous melanoma: 2-8%
        • Amelanotic Melanoma: less common
      • Biopsy:
        • Excisional biopsy (elliptical, punch [when whole lesion is small], or saucerization) with 1-3 mm margins is preferred. Avoid wider margins to permit accurate subsequent lymphatic mapping.
        • Full-thickness incisional or punch biopsy of clinically thickest portion of the lesion is acceptable in certain anatomic areas (e.g., palm/sole, digit, face and ear) or for very large lesions
        • Shave biopsy [not saucerization or deep shave] may compromise pathologic diagnosis and complete assessment of Breslow thickness but is acceptable when the index of suspicion is low.
      • Surgery:
        • Dogma about needing to do a whole elliptical excision for suspected melanoma is
        • There is evidence that a saucerization (scoop or deep shave biopsy) leads to an accurate diagnosis and staging 97% of the time.
        • Margins for surgical excision of Melanoma: WHO recommendations
          • 5mm for in situ lesions
          • 1 cm for malignant lesions less than 1.5mm in depth
          • 2 cm margins for melanomas greater than 1.5mm in thickness
        • Sentinel lymph node biopsies:
          • For tumors of greater than or equal to 1mm in depth
          • Consider for melanomas with ulceration or mitotic figures present on path
          • Metastatic workup if LN is positive.

Melanoma

Dermoscopy:

  • Helps differentiate benign from malignant
  • Miss less melanomas
  • Biopsy less benign lesions
  • Improves malignant to benign biopsy ratio

3 year risk of BCC or SCC:

  • BCC after BCC: 44%
  • SCC after SCC: 18%

Regular sunscreen use by white adults decreases the occurrence of:

  • Invasive cutaneous melanoma
  • SCC
  • NOT proven for BCC

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