Case Report
A 41-year-old man, with no past medical history, presented with multiple tumors on his forearms and trunk. Lesions started appearing in the second decade of his life. Tumors grow slowly and resolve within months leaving disfiguring scars. Physical examination revealed twenty-three erythematous, dome-shaped, cutaneous nodules of 0.5 to 3 cm diameter, with a central keratotic plug, covered with crusts and blood spots, and located on the trunk and limbs (figure 1). Some of the lesions were clustered leaving Blaschko-linear pitted scars. The conjunctiva, palms, soles, genital, and oral mucosa were not affected. Dermoscopic examination showed a central structureless red-purple keratotic crater surrounded by a structureless while area with white circles surrounding hair follicles and linear, serpentine, and looped vessels (figure 1). Histopathological examination of an excised tumor revealed a hyperkeratotic acanthotic epidermis with well-differentiated glassy keratinocytes and basal mitoses, surrounded by a polymorphonuclear inflammatory infiltrate (figure 2). Based on clinical and histopathological findings, the diagnosis of multiple KA of Ferguson-Smith type was made. Treatment with oral acitretin 20 mg/d (approximately 0.3 mg/kg of body weight) was started with marked and rapid response.