A 10-year-old boy was referred to the dermatology department with a 1-year history of what appeared to be extensive warts on both hands. On physical examination, multiple hyperkeratotic, erythematous, flat papules with central atrophy were present on the dorsum of the metacarpophalangeal and interphalangeal joints. A skin-biopsy specimen showed acanthosis, hyperkeratosis with focal vacuolar alteration of the basal-cell layer, and perivascular inflammatory infiltrates, findings that were consistent with Gottron's papules. The patient also had discrete facial heliotrope erythema.
He reported having no history of weakness, and the muscle-strength examination was normal. Laboratory evaluation revealed an elevated level of creatine kinase (290 U per liter; normal value, <190 U per liter). The results of proximal muscle electromyography and magnetic resonance imaging were normal. Source: …
