Dermatology - Common Skin Cancers

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[edit] Common skin cancers

[edit] Basal cell carcinoma (BCC)

  • Epidemiology:
    • Most common form of skin cancer in the US
    • Arises from basal cells
    • 2.8 million cases annually
    • Rarely fatal but can be highly disfiguring
    • Incidence is increasing


  • Risk factors:
    • Fair skin
    • Sun exposure
    • Family history
    • Radiation therapy
      • Used to use this for tinea treatment
    • Arsenic: think farmers
  • Prevention:
    • Use sun protection!
    • To prevent BCC, pts should self-examine for lesions
    • Pts should be examined by dermatologists frequently


  • Appearance:
    • Solitary pearly nodule with roled borders and telangiectasia and sometimes ulceration
    • Can look like scars
    • Friable (easily broken apart)
    • Look for telangiectasias
    • Bleeds easily
    • Distributed across sun exposed areas (face and arms)
    • Slow-growing, non-aggressive, rarely metastasizes
      • Can metastasize if neglected; commonly via trigeminal nerve; don't take lightly
    • Have pallisading histologically
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_07.png


  • Diagnosis:
    • The only way to definitively dx BCC (basal cell carcinoma) is to take a biopsy of the lesion.
    • Though biopsy is usually done, physical exam can often dx basal cell carcinomas


  • Course / Prognosis:
    • Basal cell carcinoma grows slowly and can have a variable course
      • 2x the size in 2 years
    • BCC often generates bleeding and ulceration
    • Beware that BCC can do extensive damage through invation into many different tissues
    • BCC very rarely metastasizes
      • Those that do metastasize are from very large primary tumors that have not been treated as they should.

[edit] Therapy

  • Treatment options include surgical, electrodessication with curettage, cryosurgery, topical therapy, and radiation therapy


  • Surgery offers the best cure rate and is most commonly chosen treatment
  • For most areas of the body, excision is the standard; on the face, Mohs Micrographic surgery is the standard.
  • The traditional surgery method was to cut a margin of 4mm.


  • More on Mohs:
    • The tumor is cut out with no margin.
    • The tumor is frozen, sectioned.
    • The margins are checked under the microscope.
    • More is excised from any area where tumor remains until margins are clear.
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_27.png


  • More on electrodesiccation and curettage (ED&C):
    • Used for smaller tumors
    • Visible tumor is scraped out and electrodessicated (cauterized) repeatedly.
    • Cosmetic results are worse than standard excision
    • Cure rate can approach that of excision
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_28.png


  • Cryotherapy (liquid nitrogen)
    • Extreme cold of liquid nitrogen kills tumor and surrounding tissue
    • -240C!
    • Not commonly done


  • Topical therapy
    • Imiquimod (aldara) has a 75-77% cure rate for superficial and nodular BCC
      • Don't need to know the drug
    • Induces an immune response against the tumor
      • Can also be used for AK and SCC
      • Don't use on deep lesions because it might remove the superficial part and hide the deep part.


  • Radiation therapy
    • Radiation therapy is good for pts with many BCCs
    • Efficacy varies by location on body
    • 3 / week for many weeks
    • Use of radiation therapy can result in the tumor returning in a more aggressive form
    • Radiation therapy is used in pts who are unable to tolerate surgery
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_31.png

[edit] Basal cell carcinoma subtypes

  • Subtypes of basal cell carcinomas include: nodular (60%), pigmented, superficial "multicentric" (15%), morpheaform / sclerosing (3%), fibroepithelioma of Pinkus (rare)


  • Superficial "multicentric":
    • Cutaneously, superficial BCC is scaly, erythematous and develops in a patch form.
    • Histologically, superficial BCC has sheets of tumor cells, immature stroma, and inflammatory infiltrate
    • Superficial basal cell carcinomas have multicentric origins 
**Wide subclinical extension
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_09.png


  • Pigmented:
    • Pigmented basal cell carcinomas resemble melanomas
    • Melanin is present in dermal macrophages and tumor cells 
How does one tell them apart
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_10.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_15.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_19.png
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    • 111014_Dermatology_09_Common_Skin_Cancers_Page_22.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_23.png


  • Morpheaform / sclerosing:
    • Morpheaform basal cell carcinoma is characterized by whitish indurations
    • Histologically, morpheaform basal cell carcinom has thin strands of tumor cells in dense, sclerotic stroma
    • Morpheaform carcinomas extend an average of 7.2 mm from the observable tumor
    • Can be mistaken as a scar.
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_11.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_17.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_21.png


  • Nodular:
    • Has rolled edges
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_09.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_14.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_19.png


  • Fibroepithelioma of Pinkus:


  • Infiltrative BCC:
    • Infiltrative basal cell carcinomas are translucent / pearly in quality with superficial blood vessles, and a depressed, scar-like appearance
    • Infiltrative BCC invade aggressively and deeply
    • Can look like scar, not much whitish
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_12.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_16.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_18.png


  • Basosquamous (metatypical BCC):
    • Metatypical BCC is "metatypical" because it has histologic characteristics of both BCC and SCC
    • Metatypical BCCs act like SCCs
    • Treat them like SCC because SCC is more serious
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_13.png



[edit] Actinic keratosis (AK)

  • Epidemiology:
    • Affects over 50% of elderly
    • Affects over 50% of fair-skinned people in hot, sunny climates
    • Actinic keratosis is a pre-SCC change!


  • Risk factors for actinic keratosis include: fair skin, a history of significan UV exposure, a family hx of AK, and immune-insufficiency


  • Pathology:
    • AK is benign BUT pre-malignant
    • <10% of AK become squamous cell carcinomas (if untreated)


  • The appearance of actinic keratosis is described as dry, erythmatous, scaly, hyperkeratotic macules and papules
    • Mostly found on the face, scalp, and arms
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_40.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_41.png


  • Diagnosis of actinic keratosis:
    • A biopsy is definitive
    • More often, dx is by physical examination
    • AK Suspected to be morphing into SCC should be biopsied!


  • Treatment for aktinic keratosis can be via cryotherapy or chemotherapy.
    • Chemotherapies include 5-fluorouracil, imiquimod, and retinoids
    • 5-fluorouracil is applied topically
    • Imiquimod, too, is a topical cream
    • Retinoids can prevent formation of AK when used regularly
      • Retinoids include tretinoin, adapalene, tazarotene, et cetera



[edit] Squamous cell carcinoma (SCC)

  • Epidemiology:
    • Second most common form of skin cancer (to BCC)
    • SCC is more prevalent than BCC: in black pts; in immune-compromised pts; on lips and dorsal hands; in PUVA treatment pts
    • Incidence is on the rise
    • AK is a precursor


  • Risk factors:
    • Fair skin
    • Sun exposure
      • AK is a precursor!
    • Family hx
    • Arsenic 
**Hydrocarbons
    • Heat
    • Radiation
    • Scars
    • Uncircumcised males (penile SCC)
    • Alcohol + tobacco (synergistic) => SCC
    • HPV


  • Clinical features:
    • Locations: face, lips, mouth, ears, dorsal hands, chest and back, anogenital, extremities


  • Appearance: small, red, hard, scaly, papules / plaques
    • Much variation
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_49.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_50.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_51.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_52.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_53.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_54.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_55.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_56.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_57.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_58.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_59.png


  • Diagnosis: PE is sufficienty; biopsy is definitive


  • Prevention:
    • Squamous cell carcinoma metastasis is rare (5% of untreated) but more common than BCC
      • As with basal cell carcinoma, the larger the primary lesion, the more likely it is to metastasize.
    • SCC in situ has a much better prognosis than invasive SCC

[edit] Therapy

  • Same as BCC: surgical, electrodessication with curettage, cryosurgery, topical therapy, and radiation therapy


  • Surgery offers the best cure rate and is most commonly chosen treatment
  • For most areas of the body, excision is the standard; on the face, Mohs Micrographic surgery is the standard.
  • The traditional surgery method was to cut a margin of 4mm.


  • More on Mohs:
    • The tumor is cut out with no margin.
    • The tumor is frozen, sectioned.
    • The margins are checked under the microscope.
    • More is excised from any area where tumor remains until margins are clear.
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_27.png


  • More on electrodesiccation and curettage (ED&C)
    • Used for smaller tumors
    • Visible tumor is scraped out and electrodessicated repeatedly.
    • Cosmetic results are worse than standard excision
    • Cure rate can approach that of excision
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_28.png


  • Cryotherapy (liquid nitrogen)
    • Extreme cold of liquid nitrogen kills tumor and surrounding tissue
    • Not commonly done


  • Topical therapy
    • Imiquimod (aldara) has a 75-77% cure rate for superficial and nodular BCC
    • Induces an immune response against the tumor


  • Radiation therapy
    • Radiation therapy is good for pts with many BCCs
    • Efficacy varies by location on body
    • 3 / week for many weeks
    • Use of radiation therapy can result in the tumor returning in a more aggressive form
    • Radiation therapy is used in pts who are unable to tolerate surgery
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_31.png




[edit] Melanoma

  • Epidemiology:
    • 68K new cases each year
    • Only 4% of skin cancer cases but 79% of skin cancer deaths
    • Incidence is rising (faster than SCC and BCC)
    • 1/55 will be dx with melanoma in their lifetime


  • Risk factors:
    • Intermittent sun exposure seems to be more risky than chronic sun exposure
    • Fair skin (sunburning easily)
    • Genetics (defective p16 tumor suppressor)
    • Family hx
    • Congenital nevi (as size increases, so does risk for melanoma)
    • Dysplastic nevi
    • Immunosuppression


  • Clinical features:
    • One should be suspicious of pigmented lesions that itch, burn, are tender, bleed, or ulcerate.
    • At early stages, unlikely to show these signs.


  • Subtypes:
    • Superfiical spreading melanoma: most common; 70% of cases
    • Lentigo maligna: means the SCC is invasive
    • Acral lentiginous: just means it is at the acral areas of the body
    • Nodular melanoma: usually invasive upon dx; deeper, able to metastasize b/c of access to blood / lymphatics


  • Appearance:
    • Most are black or brown; some are skin-colored, pink, red, purple, blue, or white
    • Use ABCDE to assess if a pigmented lesion is melanoma
      • At early stages, unlikely to show these signs.
    • Can show regression (when immune cells start attacking it and trim the border back a bit)
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_70.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_71.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_72.png
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    • 111014_Dermatology_09_Common_Skin_Cancers_Page_87.png
    • 111014_Dermatology_09_Common_Skin_Cancers_Page_88.png


  • Diagnosis:
    • Unlike SCC and BCC, melanoma can only be dx with a biopsy!
      • Any minimally suspicious lesion should be biopsied.
    • Use a dermatoscope (magnifier) to increase observation acuity.


  • Treatment:
    • Melanomas require excision
      • For small, local lesions, excision is curative
    • Distant metastases have poor prognosis: 12% survive at 5 years (with chemo- and immuno- therapy)


  • Course / Prognosis
    • Melanomas are far more likely to metastasize than SCC or BCC and thus have a poorer prognosis
    • Prognosis is poor because of mestastasis and poor treatment.
    • Poor prognosis is associated with a deeper lesions, ulcerations, and nodal formation.
    • Size is a poor prognostic indicator relative to depth.
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