Primary Primitive Neuroectodermal Tumor of the Bladder: Histologic and Clinical Features of 9 Cases

Primitive neuroectodermal tumor (PNET) is a group of malignant neoplasias of the small round cells that can occur in any part of the body. Only eight cases PNET of the bladder have been described to date. These are rare, aggressive lesions that are related to Ewing's sarcoma. Given that so few cases have been described, it is not possible to establish an appropriate diagnostic conduct and treatment, and each case described serves to increase our knowledge and help elaborate strategies for treatment. We present a ninth case, and review some aspects on the presentation, diagnosis and treatment of these lesions. As new cases are described, it will become possible to define protocols for management based on evidence.