A 78-year-old male presented complaining voiding low urinary tract symptoms associated to genital weightiness over the past few years. Grossly the lesion was only interesting the scrotum, for an about 7.5 kg mass. The scrotum was minimally tender, with an intact skin bereft of erythema or inflammation, lower limb lymphedema, inguinal/crural lymphadenopathy. Despite repeated urinary cytologies were negative, an abdominal CT and urethrocystoscopy confirmed a muscle-invasive transitional cell carcinoma affecting the bladder. The surgical strategy included a direct excision of the giant scrotum with local tissue reconstruction and a radical cystectomy with ileal conduit. This is the first time it's noted a giant scrotal lymphedema as the unique onset sign of a muscle invasive transitional cell carcinoma of the bladder otherwise clinically silent. In this clinical setting, a differential diagnosis has always to be carried out, as bladder cancer is a life-threatening disease requiring an aggressive approach.