Colon cancer presenting as amyotrophic dermatomyositis.

A 69-year-old woman presented to the medical outpatient clinic with a 1-month history of a non-pruritic rash that first affected her face, then her trunk and limbs. She had no arthralgia, myalgia or limb weakness. Examination revealed a heliotrope rash, shawl sign and Gottron papules (figure 1A, B and C). Antinuclear antibodies, myositis-specific autoantibody anti-SAE1 and myositis-associated autoantibody anti-Ro52 were detected, but C3 and C4 complements, and serum creatine phosphokinase levels were normal. Skin biopsy revealed interface dermatitis and perivascular inflammatory infiltrate, with an increase in dermal mucin …