Premalignant and Malignant Tumors

Figure 5.6 A: Syringomas (Courtesy of Dr. Paul Getz) B: Cutaneous leiomyomas (Reprint from Bolognia JL, Rapini R, Jorrizo JL. Dermatology. 2nd ed. St. Louis, MO: Mosby; 2008) C: Actinic keratosis

• Common premalignant lesion in sun-exposed areas with potential to transform into squamous cell carcinoma (percentage varies)
• Presents as erythematous macule or thin papule with adherent scale in sun-exposed areas (easier to identify with palpation)
• Histology: focal parakeratosis, atypical keratinocytes with nuclear pleomorphism and crowding (partial-thickness dysplasia), disordered maturation, prominent solar elastosis in dermis
• Variants: pigmented AK, acantholytic AK, bowenoid AK, lichenoid AK, atrophic AK, hypertrophic AK, actinic cheilitis (confluence of AKs typically on lower lip), cutaneous horn (conical excrescence)
• Treatment: cryotherapy, topical 5-fluorouracil (5-FU), topical imiquimod, chemical peels, photodynamic therapy (PDT)