Clear Cell Papulosis Christine J. Ko, MD Key Facts Terminology Rare disorder Multiple, hypopigmented to white, flat-topped papules and macules Generally on lower trunk/suprapubic area Almost always in young children…

Clear Cell Acanthoma Christine J. Ko, MD Key Facts Clinical Issues Common in middle-aged women Generally on lower legs Solitary, pink-red, shiny papule or plaque Microscopic Pathology Acanthosis of pale…

Prurigo Nodularis Christine J. Ko, MD Key Facts Etiology/Pathogenesis Chronic rubbing/scratching induces discrete papules/nodules Clinical Issues Generally on extremities but sometimes on trunk or posterior scalp Microscopic Pathology Hyperkeratosis, focal…

Large Cell Acanthoma David Cassarino, MD, PhD Key Facts Terminology Proliferation of enlarged and mildly atypical keratinocytes in sun-damaged skin without diagnostic features of actinic keratosis Variously considered to be…

Condyloma Acuminatum (Genital Wart) Elsa F. Velazquez, MD Key Facts Etiology/Pathogenesis HPV-related lesion Low-risk HPV serotypes (6, 11) predominate Macroscopic Features From flat to exophilic cauliflower-like lesions Measuring from a…

Verruca Vulgaris (and Variants) David Cassarino, MD, PhD Key Facts Terminology Verruca vulgaris (VV) Common warts Palmoplantar warts (myrmecia) Flat warts (verruca plana) Etiology/Pathogenesis Causal relationship with numerous HPV types…

Seborrheic Keratosis (and Variants) Elsa F. Velazquez, MD Key Facts Macroscopic Features Sharply delineated plaques with greasy appearance Verruciform or flat surface Surface shows characteristic keratotic plugs From flesh-colored to…

Acantholytic and Acantholytic Dyskeratotic Acanthoma Christine J. Ko, MD Key Facts Clinical Issues Generally a solitary papule Often on trunk Often submitted as “rule out basal cell carcinoma” Microscopic Pathology…

Warty Dyskeratoma Christine J. Ko, MD Key Facts Clinical Issues Solitary (very rarely multiple) Umbilicated papule or nodule Often on head or neck Microscopic Pathology Cup-shaped lesion Sometimes associated with…

Pseudoepitheliomatous Hyperplasia Christine J. Ko, MD Key Facts Terminology Pseudoepitheliomatous hyperplasia (PEH) Florid proliferation of epidermis that mimics squamous cell carcinoma Etiology/Pathogenesis Tumors Inflammatory conditions Infections Tattoos Microscopic Pathology Hyperplasia…