A man in his 80s presented to the emergency department with a 4-week history of progressive weakness and fatigue, with associated development of purple bruiselike lesions on his head. He denied any history of trauma, falls, or occlusive headgear use. His medical history was significant for atrial fibrillation, receiving anticoagulation medication, and heart failure.
On physical examination, numerous nontender violaceous plaques were seen on the forehead and scalp of the patient (Figure, A). On full skin examination, nonspecific skin-colored plaques were noted on the chest, and a 1.8 × 2.5-cm erythematous plaque was noted on the left lower back. There was no appreciable lymphadenopathy or hepatosplenomegaly. Peripheral blood test results revealed a hemoglobin level of 9.1 g/dL, a platelet count of 68 × 103/μL, a white blood cell count of 2800/μL, and an absolute neutrophil count of 1.0/μL. Lactate dehydrogenase level was 202 U/L. (To convert hemoglobin to g/L, multiply by 10.0; platelets to ×109/L, by 1; white blood cell and neutrophil counts to ×109/L, by 0.001; and lactate dehydrogenase to μkat/L, by 0.0167.) A 4-mm punch biopsy was performed on the erythematous plaque on the left lower back (Figure, B and C).