Learning Objective
At the end of this lesson, the learner should be able to identify common benign skin growths, recognize their clinical and histologic features, and differentiate them from malignant lesions.
Seborrheic Keratoses
Benign squamoproliferative neoplasms are commonly seen in middle-aged and elderly adults. They appear as tan to brown, coin-shaped plaques with a characteristic “stuck-on” appearance and a granular surface. Histology shows basaloid epidermal hyperplasia and horn cysts (keratin-filled pseudocysts). They are harmless and typically require no treatment unless symptomatic or for cosmetic removal.
Sign of Leser-Trélat: sudden onset of multiple seborrheic keratoses associated with an underlying internal malignancy (paraneoplastic).
Verrucae (Warts)
Caused by human papillomavirus (HPV). The most common type is verruca vulgaris, presenting as rough, hyperkeratotic papules.
Epidermoid Cyst
A benign cyst lined by stratified squamous epithelium and filled with keratin debris. Often presents as a firm, subcutaneous nodule.
Acrochordons (Skin Tags)
Small (<5 mm), soft, pedunculated papules are commonly found on the neck, axillae, and skin folds. Histology shows a connective-tissue stalk covered by stratified squamous epithelium. Often removed for cosmetic reasons.
