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.