Anaplastic dermatomyositis is a new type of dermatomyositis that has characteristic dermatomyositis skin changes without myositis and lasts for 24 months. It has the same high rate of concomitant malignancy as dermatomyositis and is a concomitant neoplastic connective tissue disease. There are independent diagnostic criteria for anaplastic dermatomyositis. It accounts for 5-20% of dermatomyositis, with a mean age of onset of 51.2 years and a male to female ratio of 1:1.6. Classification: dermatomyositis with characteristic dermatitis is called dermatomyositis (DM); dermatomyositis without dermatitis is called polymyositis (PM); dermatomyositis with characteristic dermatitis without myositis is called dermatomyositis without myositis. Other types include: polymyositis or dermatomyositis in children; polymyositis or dermatomyositis with connective tissue disease; polymyositis or dermatomyositis with malignancy. Clinical manifestations: Characteristic or diagnostic skin lesions include: 1. Edematous purplish spots (violet color) around the eyelids (especially purplish spots on the upper eyelids with edema around the eyelids, also known as dermatophytosis toward the positive), symmetrically distributed. There are cutaneous heterochromia-like erythematous spots on the neck, shoulders, upper chest, forearms, and upper arms (capillary dilation and mild atrophy on the skin damage. There is both hyperpigmentation and hypopigmentation). 2.Gottron papules and Gottron’s sign: There are symmetrically distributed purple-red papules on the back of finger joints, metacarpophalangeal joints, elbows and knee joints, called Gottron’s papules, and there are purple-red spots, atrophic spots or fusion into plaques (with capillary dilation, flushing and scaling) at these papules, called Gottron’s sign. 3. Capillary dilation at the nail folds (there is capillary dilation around the nail). 4.Erythema of the skin at the exposed area: edematous erythema with distinct boundaries occurs at the exposed area exposed to sunlight. Most typically seen in the V-zone of the chest or the skin outside the round neck of the round neck shirt, which is caused by photosensitivity. (The V-zone has atrophic dermatitis, erythema, dilated capillaries, and cigar paper-like wrinkles). The boundaries are clear. 5, no clinical manifestations of muscle inflammation, no muscle weakness, myalgia and myalgia. 6, muscle enzyme spectrum, electromyography, muscle biopsy, and myositis-specific antibodies were normal. Muscle imaging (thallium scan, CT, MRI, muscle ultrasonography were normal.