Amyopathic dermatomyositis (ADM) is a rare condition characterized by skin lesions suggestive of dermatomyositis (DM) without detectable muscle abnormalities after at least 2 years of follow-up. Pulmonary fibrosis is uncommon in patients with ADM.
Case report: A 64-year-old woman presented with a 2 years and 6 months history of nondestructive polyarthritis. She had skin changes suggestive of DM, including a pink rash over the face, neck, and forearms; Gottron's papules over the metacarpophalangeal joints; and heliotrope edema of the eyelids. She reported no muscle symptoms. Findings were normal from muscle enzyme assays, electromyography, and muscle biopsies. A diagnosis of ADM was given. Early lung fibrosis was found. Investigations for a tumor were negative.
Discussion: ADM is a rare condition that may be an abortive form of DM with a favorable outcome and a lower risk of malignancy compared to classic DM. However, the development of pulmonary fibrosis may cloud the prognosis.