Squamous cell papilloma is a very common benign epithelial tumour with a variable clinical appearance, including narrow-based (pedunculated or ‘skin tag’ – Fig. 1.5A), pink broad-based (sessile – Fig. 1.5B) and whitish thread-like (filiform) hyperkeratotic lesions similar to a cutaneous horn (Fig. 1.5C). Histopathology in all clinical types is similar, showing finger-like projections of fibrovascular connective tissue covered by irregular acanthotic and hyperkeratotic squamous epithelium (Fig. 1.5D). The incidence increases with age; at least some cases result from human papilloma virus infection. Treatment usually involves simple excision, but other options include cryotherapy and laser or chemical ablation.

(Courtesy of J Harry – fig. A; S Chen – fig. C)

Benign Epidermal Tumours

(Courtesy of A Pearson – fig. C; J Harry – fig. D)