Clinical introduction

A 78-year-old woman presented to the emergency department because of weakness and rapidly evolving painful skin lesions. Her medical history was unremarkable, and she was not taking any medications. Physical examination showed irregular violaceous lesions of the right lower limb (figure 1A), knees (figure 1B) and small bullae on the legs (figure 1C). Blood tests were normal; urinalysis showed gross haematuria. An ultrasound of the urinary tract showed an invasive tumour of the bladder.