Primitive neuroectodermal tumor (PNET) is part of the Ewing sarcoma family of tumors. The present case reports a primitive neuroectodermal tumor (PNET) of rare location in the bladder in a newborn. It was evaluated with prenatal ultrasound and postnatal tomography that revealed a mass in the posterior wall of the bladder. The patient underwent partial cystectomy with subsequent analysis of the surgical piece removed, the histopathological study indicated a tumor of mesenchymal origin, and immunohistochemical staining confirmed the diagnosis of PNET of the bladder. Satisfactory result and short-term follow-up. / Revisión por pares

Ewing's sarcoma family of tumors (ESFTs) contains multiple tumors with similar histological and immunohistochemical features. ESFTs are small, round cell, highly malignant tumors that arise from the neuroectoderm of bone and extraskeletal soft tissue. Ewing's sarcoma is the second most common primary malignant bone cancer in children and adolescents, with the second decade of life being the most common age of diagnosis. In this article, we present a case of a young male who presented to the emergency department complaining of shortness of breath and cough and was later diagnosed with Ewing's sarcoma of the chest wall, which is also called Askin's tumor, and it is an extremely rare disease with only 17 cases reported in the literature.