Basal Cell Carcinoma
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Questions and Answers

What is the most common cutaneous malignancy?

  • Squamous cell carcinoma
  • Keratoacanthoma
  • Malignant melanoma
  • Basal cell carcinoma (correct)

    • What is the classic location of basal cell carcinoma?

  • Lower lip
  • Nose
  • Forehead
  • Upper lip (correct)

    • What is a risk factor for squamous cell carcinoma?

  • Family history
  • Immunosuppressive therapy (correct)
  • Fair skin
  • Previous skin cancer

    • What is the precursor lesion of squamous cell carcinoma?

    <p>Actinic keratosis (D)</p> Signup and view all the answers

    What is the function of melanocytes?

    <p>Synthesize melanin (B)</p> Signup and view all the answers

    What is the underlying cause of albinism?

    <p>Enzyme defect (usually tyrosinase) that impairs melanin production (B)</p> Signup and view all the answers

    What is the characteristic appearance of basal cell carcinoma?

    <p>Elevated nodule with a central, ulcerated crater surrounded by dilated vessels (C)</p> Signup and view all the answers

    What is the treatment for squamous cell carcinoma?

    <p>Excision (C)</p> Signup and view all the answers

    Which of the following treatments is used for psoriasis?

    <p>All of the above (D)</p> Signup and view all the answers

    What is a characteristic feature of psoriatic lesions?

    <p>Well-circumscribed, salmon-colored plaques (A)</p> Signup and view all the answers

    What is the term for collections of neutrophils in the stratum corneum in psoriatic lesions?

    <p>Munro microabscesses (A)</p> Signup and view all the answers

    What is the term for the process by which keratinocytes separate from each other in pemphigus vulgaris?

    <p>Acantholysis (B)</p> Signup and view all the answers

    What is the type of hypersensitivity reaction involved in pemphigus vulgaris?

    <p>Type II hypersensitivity (C)</p> Signup and view all the answers

    What is the term for the sign where thin-walled bullae rupture easily in pemphigus vulgaris?

    <p>Nikolsky sign (A)</p> Signup and view all the answers

    What is the term for the pattern of immunofluorescence in pemphigus vulgaris?

    <p>'Fish net' pattern (A)</p> Signup and view all the answers

    What is a possible association with lichen planus?

    <p>Chronic hepatitis C virus infection (B)</p> Signup and view all the answers

    What is the risk factor associated with dysplastic nevus syndrome?

    <p>Autosomal dominant disorder (D)</p> Signup and view all the answers

    Which type of melanoma is associated with a low risk of metastasis?

    <p>Radial growth phase (B)</p> Signup and view all the answers

    What is the characteristic feature of a freckle?

    <p>Increased number of melanosomes (A)</p> Signup and view all the answers

    What is the most common type of mole in adults?

    <p>Intradermal nevus (A)</p> Signup and view all the answers

    What is the characteristic feature of melanoma?

    <p>Asymmetry and irregular borders (A)</p> Signup and view all the answers

    What is the most important prognostic factor in predicting metastasis in melanoma?

    <p>Breslow thickness (B)</p> Signup and view all the answers

    What is the risk factor associated with xeroderma pigmentosum?

    <p>Reduced protection against UVB (A)</p> Signup and view all the answers

    What is the characteristic feature of melasma?

    <p>Mask-like hyperpigmentation (A)</p> Signup and view all the answers

    Study Notes

    Skin Cancers

    • Basal cell carcinoma:
      • Most common cutaneous malignancy
      • Presents as an elevated nodule with a central, ulcerated crater surrounded by dilated (telangiectatic) vessels; 'pink, pearl-like papule’
      • Classic location is the upper lip
      • Histology shows nodules of basal cells with peripheral palisading
      • Treatment is surgical excision; metastasis is rare
    • Squamous cell carcinoma:
      • Malignant proliferation of squamous cells characterized by formation of keratin pearls
      • Risk factors include UVB-induced DNA damage, prolonged exposure to sunlight, albinism, xeroderma pigmentosum, immunosuppressive therapy, arsenic exposure, and chronic inflammation
      • Presents as an ulcerated, nodular mass, usually on the face (classically involving the lower lip)
      • Treatment is excision; metastasis is common
      • Actinic keratosis is a precursor lesion of squamous cell carcinoma and presents as a hyperkeratotic, scaly plaque, often on the face, back, or neck
      • Keratoacanthoma is a well-differentiated squamous cell carcinoma that develops rapidly and regresses spontaneously; presents as a cup-shaped tumor filled with keratin debris

    Disorders of Pigmentation and Melanocytes

    • Melanocytes:
      • Responsible for skin pigmentation
      • Present in the basal layer of the epidermis
      • Derived from the neural crest
      • Synthesize melanin in melanosomes using tyrosine as a precursor molecule
      • Pass melanosomes to keratinocytes
    • Vitiligo:
      • Localized loss of skin pigmentation
      • Due to autoimmune destruction of melanocytes
    • Albinism:
      • Congenital lack of pigmentation
      • Due to an enzyme defect (usually tyrosinase) that impairs melanin production
      • May involve the eyes (ocular form) or both the eyes and skin (oculocutaneous form)
      • Increased risk of squamous cell carcinoma, basal cell carcinoma, and melanoma due to reduced protection against UVB
    • Freckle (Ephelis):
      • Small, tan to brown macule; darkens when exposed to sunlight
      • Due to increased number of melanosomes (melanocytes are not increased)
    • Melasma:
      • Mask-like hyperpigmentation of the cheeks
      • Associated with pregnancy and oral contraceptives
    • Nevus (Mole):
      • Benign neoplasm of melanocytes
      • Congenital nevus is present at birth; often associated with hair
      • Acquired nevus arises later in life
      • Characterized by a flat macule or raised papule with symmetry, sharp borders, evenly distributed color, and small diameter (< 6 mm)
      • Dysplasia may arise (dysplastic nevus), which is a precursor to melanoma
    • Melanoma:
      • Malignant neoplasm of melanocytes; most common cause of death from skin cancer
      • Risk factors are based on UVB-induced DNA damage and include prolonged exposure to sunlight, albinism, and xeroderma pigmentosum
      • Presents as a mole-like growth with "ABCD" characteristics:
        • Asymmetry
        • Borders are irregular
        • Color is not uniform
        • Diameter > 6 mm
      • Characterized by two growth phases:
        • Radial growth horizontally along the epidermis and superficial dermis; low risk of metastasis
        • Vertical growth into the deep dermis; increased risk of metastasis; depth of extension (Breslow thickness) is the most important prognostic factor in predicting metastasis

    Psoriasis

    • Well-circumscribed, salmon-colored plaques with silvery scale, usually on extensor surfaces and the scalp; pitting of nails may also be present
    • Due to excessive keratinocyte proliferation
    • Possible autoimmune etiology
    • Associated with HLA-C
    • Lesions often arise in areas of trauma (environmental trigger)
    • Histology shows:
      • Acanthosis (epidermal hyperplasia)
      • Parakeratosis (hyperkeratosis with retention of keratinocyte nuclei in the stratum corneum)
      • Collections of neutrophils in the stratum corneum (Munro microabscesses)
      • Thinning of the epidermis above elongated dermal papillae; results in bleeding when scale is picked off (Auspitz sign)
    • Treatment involves corticosteroids, UV light with psoralen, or immune-modulating therapy

    Lichen Planus

    • Pruritic, planar, polygonal, purple papules, often with reticular white lines on their surface (Wickham striae); commonly involves wrists, elbows, and oral mucosa
    • Oral involvement manifests as Wickham striae
    • Histology shows inflammation of the dermal-epidermal junction with a 'saw-tooth' appearance
    • Etiology is unknown; associated with chronic hepatitis C virus infection

    Blistering Dermatoses

    • Pemphigus Vulgaris:
      • Autoimmune destruction of desmosomes between keratinocytes
      • Due to IgG antibody against desmoglein (type II hypersensitivity)
      • Presents as skin and oral mucosa bullae:
        • Acantholysis (separation) of stratum spinosum keratinocytes (normally connected by desmosomes) results in suprabasal blisters
        • Basal layer cells remain attached to basement membrane via hemidesmosomes ('tombstone' appearance)
        • Thin-walled bullae rupture easily (Nikolsky sign), leading to shallow erosions with dried crust
        • Immunofluorescence highlights IgG surrounding keratinocytes in a 'fish net' pattern

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    Description

    A type of skin cancer that originates from the basal cells of the epidermis. It is the most common cutaneous malignancy, often caused by UVB-induced DNA damage. It presents as a pink, pearl-like papule with dilated vessels.

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