Buttonhole sign in anetoderma

A 29-year-old woman presented with a 6-month history of slack, circumscribed skin on her right neck, characterized by a soft, protuberant plaque and a positive ‘buttonhole’ sign. Histopathology revealed perivascular lymphocytic infiltration and loss of elastic fibres, leading to a diagnosis of anetoderma, an elastolytic disorder more common in young women. Although autoimmune factors like antiphospholipid antibodies can be implicated, her autoimmune profile was negative, and surgical excision was performed due to cosmetic concerns.