Title: GZ / The Grenz Zone Season 2 / 17 Actinic Keratosis/Squamous Cell Carcinoma
Tags: GZ DermnetNZ

Q: Actinic Keratosis are premalignant lesions of [...] that clinically present as erythematous and scaly macules, papules, or plaques on sun-exposed areas
A: squamous cell carcinoma
Back Extra: about 10% of AK's will progress to SCC over the course of 10 years

Q: Some clinical variants of actinic keratosis are [...] and [...]
A: hypertrophic; cutaneous horn
Back Extra: Clinical pearl: about 20% of cutaneous horns can have SCC at the base and should be biopsied with a scoop to rule out malignancy

Q: An actinic keratosis that presents on the lip is called [...]
A: actinic cheilitis
Back Extra: Actinic cheilitis will blur the border between the vermillion and cutaneous lip. Think of this if you see scaliness on the lower lip of a patient with extensive sun damage.

Q: On histology, actinic keratosis presents with atypia starting in the [specific skin layer] that is restricted to 1/3 or 2/3 of the epidermis, parakeratosis, and a background of solar elastosis
A: basal layer

Q: The most common treatment of actinic keratosis is [...]
A: cryotherapy

Q: What is the boiling point of liquid nitrogen?
[...]
A: -196⁰ Celsius or -321⁰ Fahrenheit

Q: Treatment options for multiple actinic keratosis other than cryotherapy include [...] and [...]
A: PDT (photodynamic therapy); topical chemotherapy
Back Extra: topical chemotherapy = 5-fluorouracil, imiquimod
Clinical pearl: recent literature has shown that 5-FU in combo with calcipotriene has a greater efficacy & tolerability

Q: Squamous cell carcinoma is the [1st or 2nd] most common skin cancer and is more aggressive than BCC
A: 2nd

The 4 main clinical variants of squamous cell carcinoma are keratoacanthoma, bowenoid papulosis, Bowen's disease, and Erythroplasia of Queyrat

Q: The BIGGEST risk factor for squamous cell carcinoma is [...]
A: chronic UV exposure
Back Extra: Other risk factors include ionizing radiation, medications, immunosuppression, chronic scars, HPV, etc.

Q: Some risk factors for SCC metastases are tumor diameter > [...], Breslow depth > [...], and perineural invasion > [...]
A: 2cm; 2mm; 0.1mm
Back Extra: others risk factors include SCC within wounds, tumor location on the lip or ear, recurrent SCC's, and immunosuppresion

Q: The pathogenesis of SCC is thru mutations in [...]
A: p53

Q: Clinically, [...] presents as a pink to red papule, plaque, or nodule with scale, erosion, ulceration, or pigment
A: squamous cell carcinoma

Q: [...] is a clinical variant of squamous cell carcinoma that presents as a dome-shaped nodule with a central keratin plug
A: Keratoacanthoma

Q: [...] is a syndrome that presents with multiple keratocanthomas that develop on patient's in their teens and 20's
A: Ferguson-Smith Syndrome
Back Extra: Lesions are usually localized
Compare with Gryzbowski syndrome which is generalized and in older adults

Q: [...] is a syndrome that presents with multiple smaller keratoacanthomas in older adults
A: Gryzbowski syndrome
Back Extra: 3 G's = Gryzbowski, grown-ups, generalized

Q: HPV-induced genital warts leading to squamous cell carcinoma in situ in younger patients is known as [...]
A: Bowenoid Papulosis
Back Extra: Recall the high risk HPV strains: 16,18,31,33

Q: Squamous cell carcinoma in situ anywhere on the body is also referred to as [...]
A: Bowen's disease

Q: Squamous cell carcinoma in situ on the glans penis is referred to as [...]
A: Erythroplasia of Queyrat

Q: A clinical variant of squamous cell carcinoma that presents as a massive wart(s) in the genital region is also known as [...]
A: Buschke-Lowenstein
Back Extra: Caused by HPV 6 and 11

Q: [...] is a slow-growing verrucous variant of squamous cell carcinoma that affects the bottom of the foot
A: Epithelioma cuniculatum
Back Extra: Caused by HPV 6 and 11

Q: [...] is a clinical variant of squamous cell carcinoma that presents as multiple wart-like lesions in the mouth
A: Oral Florid Papillomatosis

Q: On histology, [BCC or SCC] presents with nests of epithelial cells arising from the epidermis, full thickness atypia, variable keratinization (keratin pearls), and loss of [what epidermal layer] with surface parakeratosis
A: squamous cell carcinoma; granular layer
Back Extra: Full thickness atypia consists of malignant cells with abundant eosinophilic cytoplasm and hyperchromasia

Q: Common treatments for squamous cell carcinoma include [common surgical treatment], wide local excision, ED&C, and 5-FU (used only for SCC in-situ)
A: Mohs