Pseudosarcoma of the bladder associated with residual urachus in a 3-year-old girl

Bladder pseudosarcoma or pseudosarcomatous myofibroblastic proliferation (PMP) is a rare but nevertheless very important differential diagnosis of any bladder mass. In childhood most such masses are usually malignant soft-tissue sarcomas, and distinction from these is therapeutically crucial. To date no aetiological factor for PMP has been identified in children, and treatment is limited to surgical intervention with no role for chemotherapy or radiotherapy. We report clinical, anatomical, and histological findings in a 3-year-old girl with a pseudosarcoma of the urinary bladder associated with a residual urachus, suggesting this as the originating tissue.