A 40-year-old woman presented with rapidly progressive quadriparesis and severe weight loss. Examination disclosed global amyotrophy, absent deep tendon reflexes and malignant acanthosis nigricans (Figure) . Neurophysiologic studies disclosed pure motor neuronopathy. Paraneoplastic screening with fullbody CT/MRI scan revealed an intravesical mural lesion ( Figure) and urethrocystoscopy showed low-grade papillary urothelial carcinoma of the urinary bladder. High-titer serum anti-Hu antibodies

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... e identified. There was marked motor and dermatological improvement after lesion removal, combined with intravenous immunoglobulin and methylprednisolone. Dermatological signs are key diagnostic clues in the suspicion of underlying malignancies 1 , including rarely urological malignancies 2 , in the context of paraneoplastic motor neuronopathy 3,4 .